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Fujisan

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  • Japan
  • Stratovolcano
  • 1708 CE
  •  
  • Country
  • Primary Volcano Type
  • Last Known Eruption
  •  
  • 35.361°N
  • 138.728°E

  • 3776 m
    12388 ft

  • 283030
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number
Most Recent Weekly Report: 16 May-22 May 2001 Citation IconCite this Report

Based on information from JMA, VRC reported that 67 earthquakes occurred at Mt. Fuji on 30 April, which was the highest number since 53 earthquakes occurred on 18 December 2000. Activity had been relatively low since January 2001. During 3-9 May ~130 predominately low-frequency earthquakes occurred that were located ~15 km beneath an area just NE of the volcano's summit. No other anomalous volcanic activity was observed by NIED.

Source: Volcano Research Center-Earthquake Research Institute (University of Tokyo)


Most Recent Bulletin Report: March 2013 (BGVN 38:03) Citation IconCite this Report

2000-2001 epicenter migration; deep magma; 2011 M 6 aftershock at volcano

Fuji remains non-eruptive. Fujita and others (2013) investigate the likelihood that Fuji may erupt due to the 2011 E Shizuoka earthquake (M 6) centered on the volcano. Our previous reports of February 2001 (BGVN 26:02) and September 2001 (BGVN 26:09) described the 2000-2001 deep low-frequency (DLF) earthquake swarm under Fuji. In the first section below, we summarize work by Ukawa (2005) and Nakashimi and others (2004) who provide further details and analysis of DLF swarm activity, and discuss midcrustal, low-frequency earthquakes (MLFs) recorded during 1998-2003. Discussion in those papers noted likely molten material at depth below the volcano.

The next section reports the stress-field and pressure changes to Fuji's magmatic system due to the 11 March 2011 Tohoko megathrust, an MW 9 earthquake, which created the tsunami that devastated parts of costal NE Honshu including the Fukushima nuclear power plant. In addition, an MW 5.9 aftershock was centered below Fuji. Fujita and others (2013) assessed the possibility that the stress-field and pressure changes could enable magma to escape to the surface. Although they concluded that preexisting faults could rupture the chamber walls, the changes were seemingly insufficient to do so, suggesting no eruption was imminent.

Background. During the early 1980s, the National Research Institute for Earth Science and Disaster Prevention (NIED) installed the Kanto-Tokai seismic network in central Japan (figure 2). Later refinements included adding stations SSN and SHJ (not shown), and in the 1990s, stations, FJN, FJY, FJS and FJH, each with three component seismometers and two component tiltmeters at the bottom of 200-m-deep boreholes. In April 1995, Mt Fuji seismic data recording began using the constellation of stations.

Figure (see Caption) Figure 2. (Main map) Mt. Fuji seismic stations shown on a contour map with elevation contours at 500 m intervals. Symbols as follows: crosses, permanent stations maintained by ERI; diamond, Mt. Fuji summit Weather Station maintained since 1987 by JMA; and open circles, stations maintained by NIED. Stations FJH, FJN, FJS and FJY have borehole tiltmeters and 3-component short-period seismometers installed at 200 m depth. (inset map) Tectonic map, with solid lines indicating Eurasian (EUR), N American (NAM) and Philippine Sea (PHS) plate boundaries. Taken from Nakamichi and others, 2004.

The Fuji DLF earthquake epicenters were located using 1987 to 2001 data from the early 1980 Kanto-Tokai seismic network and later data taken at the four Fuji stations installed in 1990 (figure 3). Nakamichi and others (2005) reexamined epicenter locations of Ukawa (2004). JMA updated safety and evacuation plans.

Figure (see Caption) Figure 3. Cumulative number of DLF events (dotted curve) at Fuji during 1980-2004 and their cumulative wave energy (solid line). Note new instruments and processing accounted for some of the increase seen in 2000-2001 (right of the vertical line), however there was a clear marked increase in events there. After Ukawa (2005).

DLFs during 2000-2001. Ukawa (2005) examined the 2000-2001 DLF swarm beneath Fuji. The typical activity here since the early 1980s was 10-20 earthquakes a year at midcrustal depth described as burst-like activity lasting from several minutes to 30 minutes.

The cumulative occurrence of DLF earthquakes their associated cumulative wave energy are plotted in figure FUJ2. The cumulative number rate, or the slope of the curve, is almost constant between 1980-1995, followed by several small slope changes before the later months of 2000 due to the improvements in the seismic network and the new data processing system. The sharp increase in 2000-2001 is far larger than the increase due to the enlarged seismic network. In total, 286 events were identified during the eight months from October 2000 to May 2001. The wave energy increased to approximately twice the average recorded during the prior years.

Regarding Fuji, Ukawa (2005) notes, "On the basis of the DLF earthquake observations by the NIED seismic network, we investigated the temporal change of their occurrence rate from 1980 to 2003 and the hypocenter locations from 1987 to May 2001. The occurrence rate and the seismic wave energy release rate show an abrupt increase from October 2000 to May 2001, suggesting a change in the environment. ...Relocation of hypocenters of the DLF earthquakes indicates that hypocenters of the DLF earthquakes cluster mainly in an elongated region measuring 5 km along the long axis in a NW-SE direction, the center of which is located about 3 km NE from the summit. In addition to the main cluster, hypocenters extend to the southwest from the summit. During the swarm activity in 2000 to 2001, activity in the primary hypocenter region on the northeastern side of Mount Fuji increased greatly. The focal depths of well located DLF events range from 10 to 20 km. The sharp increase of DLF earthquake activity at Mount Fuji began soon after magma discharge and intrusion events in the Miyake-jima and Kozu-shima region in July and August 2000. These events may have modified the state of the deep magmatic system beneath Mount Fuji, thus triggering the DLF earthquake swarm."

Figure 4 shows the three volcanoes mentioned above: Fuji, Miyake-jima, and Kozu-shima. Several more volcanoes also of Holocene age did not erupt.

Figure (see Caption) Figure 4. Ukawa (2005) noted the 2000-2001 DLF swarm beneath Fuji occurred soon after the July-August 2000 magma discharge and intrusion events located at Kozu-shima and Miyake-jima. Those two volcanoes are located in the Pacific ~135 km from Fuji. Fuji did not erupt. The yellow triangles show locations of other Holocene volcanoes listed in the GVP database. Like Fuji, these also did not erupt. Base map courtesy of the Microsoft Corporation with labels by BGVN editors.

MLF earthquakes during 1998-2003. Nakamichi and others (2004) revisited Fuji MLF data, that like the DLFs of 2000-2001, they also clustered near the summit. "We have determined the hypocenter locations of MLFs using the hypoDD program [a double-difference algorithm; Waldhauser and Ellsworth, 2000] and repicked arrival times from the seismic networks of ERI, JMA and NIED in and around Mt. Fuji between 1998 and 2003 including the active periods from September 2000 to May 2001, [figure 5]".

Figure (see Caption) Figure 5. Comparison between the Fuji hypocenters of the MLFs by Nakamichi and others (2004) (red circles) and the routine processing at NIED (black circles). (a) Map view of hypocenters, (b) E-W cross-section, and (c) N-S cross-section. Taken from Nakamichi and others (2004).

The authors summarized their results as follows: "(1) Hypocenters of MLFs define an ellipsoidal volume, 5 km in diameter ranging from 11 to 16 km in focal depth. (2) This volume is centered at 3 km NE of the summit and its long axis is trending NW. This orientation coincides with the major axis of tectonic compression around Mt. Fuji. (3) The center of the MLF epicenters migrated upward and 2-3 km from SE to NW in 1998-2001."

Nakamichi and others, (2004) continue, "We interpret that the hypocentral migration of MLFs reflects magma movement associated with a NW-SE oriented dike beneath Mt. Fuji, figure 6. The relative error ranges of the hypocenters relocated here are from 100 to 500 m horizontally and from 200 to 700 m vertically. No elongated structure in the direction of the observed NW- SE strike is observed in the simulations, indicating that the observed strike is not an artifact of the relocation procedure [seen in Figure 6b along the plane A-A']. The extent of this depth range is also supported by the spread in S-P readings for individual earthquakes. S-P arrival time differences for well-recorded MLFs at station KMR range from 1.9 to 2.4 s, verifying that MLFs beneath Mt. Fuji span a depth range of at least 4 km, and are not confined to a very small volume."

Figure (see Caption) Figure 6. Hypocentral distributions of the Fuji MLFs, as determined by the hypoDD program. (a) Map view of relocated hypocenters. Hypocenters at the intersection of A-A' with B-B' shown enlarged as a circle above and to the right. (b) Cross-section A-A'. (c) Cross-section B-B'. Cross-sections A-A' and B-B' include earthquake hypocenters projected from up to 10 km on either side of the cross section line. Taken from Nakamichi and others, 2004.

The MLFs also shifted with time. The spatial and temporal variations of MLF hypocenters plotted on figure 7. Nakamichi and others (2004) observed focal depths of MLFs in 1998- 1999 that were 12-16 km deep and "seemed to move deeper gradually."

Figure (see Caption) Figure 7. Spatial and temporal variations of the Fuji hypocenters of 1998-2003 MLFs. Top plot records distances from hypocenters on the NW-SE horizontal plane projected to zero on the line A-A' of Figure 6. Bottom plot records focal depths vs. time projected to the vertical plane through A-A'. Some or all these variations were interpreted as a manifestation of magma recharge and migration. Nakamichi and others, 2004.

Two key points from Nakamichi and others (2004) were (1) the MLF processing indicated that the hypocenters migrated 2-3 km upward during 1998-2001, and (2) they interpreted the MLF hypocenter migration as reflecting magma movement associated with a NW-trending dike beneath Fuji.

2011 Fuji stress change after the MW 9 Tohoko earthquake. Fujita and others (2013) studied the Tohoko earthquake and aftershocks in order to see whether the changes in the stress field and pressure changes would cause the known active magma system to erupt. The Tohoku earthquake, MW~9, struck on 11 Mar 2011. Extension occurred over a wide region of the Japanese mainland (Fujita and others, 2013). Aftershocks included those at N Nagano (MW 6.3) on 12 March, at E Shizoka (MW 5.9) on 15 March, and at N Ibaraki (MW 5.8) on 19 March, figure 8. The E Shizuoka aftershock struck beneath Fuji's S flank above its magma system. Fujita and others (2013) selected parameters of the two highest magnitude Tohoko earthquakes from Ozawa et al. (2011) plus the E. Shizuoka earthquake to investigate the change below Fuji. Using seismic data and later modeling they found the change in static pressure below Fuji insufficient to cause an eruption.

Figure (see Caption) Figure 8. A map showing Fuji on Honshu Island with a 500 x 200 km box enclosing the epicenters in the main sequence of the Tohoko megathrust earthquake. Epicenters of key aftershocks are shown as blue stars and one green star. The later struck 15 March, 4 days after the main event at 7-12 km depth below Fuji. After Fujita and others, 2013.

The fault parameters of the Tohoko earthquakes (Table 3) were estimated by Ozawa and others (2011). With regard to the E Shizouka earthquake, Fujita and others (2013) determined the East Shizuoka source fault using the method of Ueda and others (2005) and "determined the best-fit fault model to be almost strike-slip with some reverse components, located a few kilometers south of the summit trending from depths of 7-12 km." Note that on table 3 the "Depth (top)" value of 7 km locates the top of the fault.

Table 3. Fault parameters computed for two of the strongest Tohoku earthquakes and the E Shizuoka aftershock. Tohoku parameters are from Ozawa and others (2011); those for the E Shizuoka were obtained by applying the method of Ueda and others (2005). Taken from Fujita and others (2013).

Parameters Tohoku 1 Tohoku 2 East Shizuoka
Latitude 38.80°N 37.33°N 35.3161°N
Longitude 144.00°E 142.80°E 138.7130°E
Depth (top), km 5.1 17 7
Length, km 186 194 6
Width, km 129 88 8
Strike, degrees 203 203 24
Dip, degrees 16 15 80
Rake, degrees 101 83 20
Dislocation, m 24.7 6.1 0.86
Magnitude 8.8 8.3 6.0

Figure 9 shows the distribution of hypocenters of both tectonic (blue) and DLP (red) earthquakes during 1996-2011. Tectonic earthquakes occurring during 1996-2011 (blue circles) cluster to the S at ~5-15 km depth and NE from ~17 km deep to below the 25 km scale limit with little temporal change in number until a detectable rate rise in early 2011. Hypocenters of DLFs occurring during 1996-2011 (red circles) cluster nearest the crater N at ~10-15 km depth with little temporal change in number until a detectable rate rise in early 2011. The largest event shown, the E Shizuoka tectonic earthquake (15 March 2011) occurred on the S flank of Mount Fuji at a depth of 12 km (table 3 lists the top of the fault at 7 km). Remote aftershocks were centered a few kilometers N of the summit. Taken from Fujita and others (2013).

Figure (see Caption) Figure 9. Mt Fuji summit, yellow triangle, shown with tectonic and DLF earthquakes during 1996 to 2011. Red circles correspond to hypocenters of Deep Long Period (DLP) events, and blue circles correspond to tectonic earthquakes. Note the DLP increase in 2000 and 2001, shortly after the Miyake-jima volcano eruption and huge ground deformation on Izu peninsula ~100 km SE of Mount Fuji. Courtesy of Fujita and others (2013).

The relocated hypocenters computed by Fujita and others (2013) compared to the hypocenters of the same events routinely obtained by NIED (Ukawa, 2001), showed improvement in location accuracy (figure 10). The hypocenters by NIED are distributed in a larger volume and not along a particular plane while in this study they are much more concentrated and trending NNE. As seen on figure FUJ 9, Fujita and others (2013) noted "The dislocation was 86 cm toward the NNE with a strike of 240, dip of 800, and rake of 200." Aftershocks of the E Shizouka earthquake also occurred along this fault."

Figure (see Caption) Figure 10. Topographic station location map of Fuji showing an estimated dislocation of 86 cm along a 6x6 km fault plane based on GPS data from NIED and Graphical Survey Institute (GEONET) data. Observed (red) and calculated (blue) displacement vectors are shown. Courtesy of Fujita and others (2013).

The static stress change caused by the E Shizouka earthquake was on the order of 0.1-1 MPa, or 0.2%, at the boundary of the magma reservoir, which was theoretically sufficient to trigger an eruption (Walter and others 1997; Walter and others 2009).

The deformation of Fuji's magma system was based on finite-element modeling of the Japanese mainland and Fuji seismic tomography. At Fuji, the stress changes to the magma reservoir were on the order of 0.001-0.01 MPa for the Tohoku earthquake and 0.1-1 MPa for the East Shizuoka earthquake (Fujita and others, 2013). Were these static stress changes sufficient to promote new fractures at the magma reservoir wall and magma injection? Fujita and others, 2013 maintain, "This is less than the magnitude required to break new faults but could trigger some perturbation in unstable faults or in the hydrothermal and magmatic systems. However, the magma beneath Mount Fuji does not seem to have enough potential to erupt at this moment".

References. Fujita, E., Kozono, T., Ueda, H., Kohno, Y., Yoshioka, S., Toda, N., Kikuchi, A., and Ida, Y. 2013, Stress field change around the Mount Fuji volcano magma system caused by the Tohoku megathrust earthquake, Japan. Bulletin of Volcanology, 75(1), 1-14.

Koyama M., 2002, Mechanical coupling between volcanic unrests and large earthquakes: a review of examples and mechanics. J Geogr 111:222-232, in Japanese with English abstract.

Koyama M., 2007, Database of eruptions and other activities of Fuji Volcano, Japan, based on historical records since AD 781. Yamanashi Institute of Environmental Sciences, Fuji Volcano, pp 119- 136, in Japanese with English abstract.

Nakamichi H., Ukawa, M., Sakai S., 2004, Precise hypocenter locations of midcrustal low-frequency earthquakes beneath Mt. Fuji, Japan, Earth, Planets and Space, 56, e37-e4.

Nakamichi, H., Hamaguchi , H. Tanaka S., Ueki S., Nishimura T., Hasegawa A., 2003, Source mechanisms of deep and intermediate-depth low frequency earthquakes beneath Iwate volcano, northeastern Japan, Geophysical Journal International, 154, 811-828.

Nishimura T., Ozawa S., Murakami M., Sagiya T., Tada T., Kaidzu M., Ukawa M., 2001, Crustal deformation caused by magma migration in the northern Izu Islands, Japan. Geophysical Research Letters 28:3745-3748.

Ozawa S., Nishimura T., Suito H., Kobayashi T., Tobita M., Imakiire T., 2011, Coseismic and postseismic slip of the 2011 magnitude-9 Tohoku-Oki earthquake. Nature 475:373-377.

Ueda H., Fujita E., Ukawa M., Yamamoto E., Irawan M., Kimata F., 2005, Magma intrusion and discharge process at the initial stage of the 2000 activity of Miyakejima, Central Japan, inferred from tilt and GPS data. Geophysical Journal International 161:891-906.

Ukawa, M., 2005, Deep low-frequency earthquake swarm in the mid crust beneath Mount Fuji (Japan) in 2000 and 2001, Bulletin of Volcanology, 68 (2005), pp. 47-56.

Waldhauser, F. and W. L. Ellsworth, 2000, A double-difference earthquake location algorithm: Method and application to the northern Hayward fault, California, Bull. Seismol. Soc. Am., 90, 1353-1368.

Walter T., 2007, How a tectonic earthquake may wake up volcanoes: stress transfer during the 1996 earthquake-eruption sequence at the Karymsky Volcanic Group, Kamchatka. Earth and Planetary Science Letters 264:347-359.

Walter T., Amelung F., 2007, Volcanic eruptions following M≥9 megathrust earthquakes: implications for the Sumatra-Andaman volcanoes. Geology 35:539-542.

Walter, T., Wang, R., Zimmer, M., Grosser, H., Luhr, B., and Ratdomopurubo, A., 2007, Volcanic activity influenced by tectonic earthquake: static and dynamic stress triggering at Mt. Merapi. Geophysical Research Letters 34:L05304.

Walter, T., Wang, R., Acocella, V., Neri, M., Grosser, H., and Zschau, J., 2009, Simultaneous magma and gas eruptions at three volcanoes in southern Italy: an earthquake trigger? Geology 37:251-254.

Information Contacts: National Research Institute for Earth Science and Disaster Prevention (NIED), 3-1 Tennodai, Tsukuba-shi, Ibaraki-ken, 305, Japan (URL: http://www.bosai.go.jp); Japan Meteorological Agency (JMA), Volcanological Division, 1-3-4 Ote-machi, Chiyoda-ku, Tokyo 100, Japan (URL: http://www.jma.go.jp/); Volcano Research Center, Earthquake Research Institute (ERI), University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-0032, Japan (URL: http://www.eri.u-tokyo.ac.jp/VRC/index_E.html).

Weekly Reports - Index


2001: January | May


16 May-22 May 2001 Citation IconCite this Report

Based on information from JMA, VRC reported that 67 earthquakes occurred at Mt. Fuji on 30 April, which was the highest number since 53 earthquakes occurred on 18 December 2000. Activity had been relatively low since January 2001. During 3-9 May ~130 predominately low-frequency earthquakes occurred that were located ~15 km beneath an area just NE of the volcano's summit. No other anomalous volcanic activity was observed by NIED.

Source: Volcano Research Center-Earthquake Research Institute (University of Tokyo)


24 January-30 January 2001 Citation IconCite this Report

According to a Reuters article from 29 January, the high number of low-frequency earthquakes that were recorded at Fuji over the past several months (133 in October, 222 in November, and 144 in December) decreased to 36 in January.

Source: Reuters


17 January-23 January 2001 Citation IconCite this Report

Several news reports have noted abnormally high earthquake activity during the past several months at Fuji. Usually 1 to 2 low-frequency earthquakes per month are recorded; but recent monthly counts were 35 for September 2000, 133 for October, 222 for November, and 143 for December. No other measured parameters changed at the volcano. While the earthquake counts are abnormally high, scientists do not believe that they are indicative of an imminent eruption. The volcano is being carefully monitored.

Sources: New York Times; New York Times


Bulletin Reports - Index

Reports are organized chronologically and indexed below by Month/Year (Publication Volume:Number), and include a one-line summary. Click on the index link or scroll down to read the reports.

08/1987 (SEAN 12:08) Earthquake swarm below summit probably tectonic

02/1996 (BGVN 21:02) Low-frequency earthquake swarm

02/2001 (BGVN 26:02) September 2000-January 2001 swarm includes less than or equal to M 2.2 earthquakes but lacks geodetic changes

09/2001 (BGVN 26:09) April-May 2001 earthquakes located at 15 km depth NE of the summit

03/2013 (BGVN 38:03) 2000-2001 epicenter migration; deep magma; 2011 M 6 aftershock at volcano




Information is preliminary and subject to change. All times are local (unless otherwise noted)


August 1987 (SEAN 12:08) Citation IconCite this Report

Earthquake swarm below summit probably tectonic

About nine small earthquakes of M < 2 occurred beneath the summit 20 August-1 September. Four were felt at intensities of I-III (JMA scale) by personnel at the summit meteorological observatory, but were not felt at the weather station 19 km ESE of the summit. Seismographs confirmed that the earthquakes originated just underneath the summit. JMA installed a portable seismograph at the summit on 25 August. The strongest earthquake, on 20 August at 0556, had a magnitude of 1.8 (table 1). No signs of wall collapse or landslides were observed by a field survey group around the summit that day. Earthquakes on 20 and 24 August were recorded by the Univ of Tokyo's Earthquake Research Institute seismographs within 20 km of the summit.

Table 1. Earthquakes at Mt. Fuji, 20 August-1 September 1987.

Date Time Magnitude Notes
20 Aug 1987 0556 1.8 felt at summit
23 Aug 1987 approx. 0100 not recorded felt at summit
24 Aug 1987 0630 1.4 felt at summit
27 Aug 1987 0624 less than 1 --
27 Aug 1987 0626 less than 1 felt at summit
28 Aug 1987 1355 less than 1 --
29 Aug 1987 1951 less than 1 --
01 Sep 1987 2335 less than 1 --

Small earthquakes are not rare at Fuji, but because the earthquakes occurred in the summit region during the height of the climbing season, there was some concern among government officials. However, the relatively sharp P-wave arrivals suggest that the earthquakes were tectonic in origin.

Information Contacts: Yoshiaki Ida and Harry Glicken, Earthquake Research Institute, Univ of Tokyo; JMA.


February 1996 (BGVN 21:02) Citation IconCite this Report

Low-frequency earthquake swarm

On 20, 24, 25, and 30 January about a dozen low-frequency earthquakes were recorded.

Information Contacts: Volcanological Division, Japan Meteorological Agency, 1-3-4 Ote-machi, Chiyoda-ku, Tokyo 100, Japan


February 2001 (BGVN 26:02) Citation IconCite this Report

September 2000-January 2001 swarm includes less than or equal to M 2.2 earthquakes but lacks geodetic changes

According to the Japan Meteorological Agency (JMA), a relatively large number of low-frequency, low-magnitude earthquakes have occurred at ~15 km depth below Fuji volcano since September 2000 (table 2, figure 1). For comparison, during recent years before this spike, the number of earthquakes had averaged only 1-2 per month. The maximum earthquake magnitude during September 2000-January 2001 was M 2.2, recorded on 11 October. During November-December earthquakes with M > 2.0 occurred 7 times. Earthquake hypocenters were generally located below an area NE of the summit. Geodetic parameters measured by GPS, EDM, and tilt-meters did not escalate. Located 150 km W of Tokyo, Fuji's close proximity encouraged the installation of enhanced instrumentation in order to better monitor the volcano. Previous seismic swarms at Fuji in 1987 and 1996 (SEAN 12:08 and BGVN 21:02) had lower event counts than the current episode.

Table 2. Seismic events registered at Fuji during September 2000-January 2001. Data courtesy of JMA and Reuters.

Month Seismic Events
Sep 2000 35
Oct 2000 133
Nov 2000 222
Dec 2000 144
Jan 2001 36
Figure (see Caption) Figure 1. Latitude, longitude, depth, and magnitude of seismicity at Fuji during September 2000-February 2001. Earthquake cross-sections are shown in N-S (upper right) and E-W (bottom) planes. Figure by Shin-ichi Sakai; courtesy of Setsuya Nakada (VRC-ERI).

Information Contacts: National Research Institute for Earth Science and Disaster Prevention, 3-1, Tennodai, Tsukuba-shi, Ibaraki-ken, 305, Japan (URL: http://www.bosai.go.jp/); Setsuya Nakada, Hidefumi Watanabe, and Shin-ichi Sakai, Volcano Research Center, Earthquake Research Institute, University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-0032, Japan (URL: http://www.eri.u-tokyo.ac.jp/VRC/index_E.html); Japan Meteorological Agency, Volcanological Division, 1-3-4 Ote-machi, Chiyoda-ku, Tokyo 100, Japan (URL: http://www.jma.go.jp/); Reuters (URL: http://www.reuters.com/).


September 2001 (BGVN 26:09) Citation IconCite this Report

April-May 2001 earthquakes located at 15 km depth NE of the summit

Earthquakes increased at Fuji during April-May 2001. According to the Japan Meteorological Agency 67 earthquakes were detected on 30 April. This was the highest daily number since the 53 that occurred on 18 December 2000, even though seismic activity had been relatively low since the beginning of the year. During the week of 3-9 May 2001 the number of weekly earthquakes was as high as 130. Since September 2000 most of the earthquakes were of low magnitude and low frequency. Their hypocenters were NE of the summit at ~15 km depth. The monitoring system of National Research Institute for Earth Science and Disaster Prevention had not detected any other anomalous signs.

Information Contacts: National Research Institute for Earth Science and Disaster Prevention, 3-1 Tennodai, Tsukuba-shi, Ibaraki-ken, 305, Japan (URL: http://www.bosai.go.jp/); Setsuya Nakada, Hidefumi Watanabe, and Shin-ichi Sakai, Volcano Research Center, Earthquake Research Institute, University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-0032, Japan (URL: http://www.eri.u-tokyo.ac.jp/VRC/index_E.html); Japan Meteorological Agency, Volcanological Division, 1-3-4 Ote-machi, Chiyoda-ku, Tokyo 100, Japan (URL: http://www.jma.go.jp/).


March 2013 (BGVN 38:03) Citation IconCite this Report

2000-2001 epicenter migration; deep magma; 2011 M 6 aftershock at volcano

Fuji remains non-eruptive. Fujita and others (2013) investigate the likelihood that Fuji may erupt due to the 2011 E Shizuoka earthquake (M 6) centered on the volcano. Our previous reports of February 2001 (BGVN 26:02) and September 2001 (BGVN 26:09) described the 2000-2001 deep low-frequency (DLF) earthquake swarm under Fuji. In the first section below, we summarize work by Ukawa (2005) and Nakashimi and others (2004) who provide further details and analysis of DLF swarm activity, and discuss midcrustal, low-frequency earthquakes (MLFs) recorded during 1998-2003. Discussion in those papers noted likely molten material at depth below the volcano.

The next section reports the stress-field and pressure changes to Fuji's magmatic system due to the 11 March 2011 Tohoko megathrust, an MW 9 earthquake, which created the tsunami that devastated parts of costal NE Honshu including the Fukushima nuclear power plant. In addition, an MW 5.9 aftershock was centered below Fuji. Fujita and others (2013) assessed the possibility that the stress-field and pressure changes could enable magma to escape to the surface. Although they concluded that preexisting faults could rupture the chamber walls, the changes were seemingly insufficient to do so, suggesting no eruption was imminent.

Background. During the early 1980s, the National Research Institute for Earth Science and Disaster Prevention (NIED) installed the Kanto-Tokai seismic network in central Japan (figure 2). Later refinements included adding stations SSN and SHJ (not shown), and in the 1990s, stations, FJN, FJY, FJS and FJH, each with three component seismometers and two component tiltmeters at the bottom of 200-m-deep boreholes. In April 1995, Mt Fuji seismic data recording began using the constellation of stations.

Figure (see Caption) Figure 2. (Main map) Mt. Fuji seismic stations shown on a contour map with elevation contours at 500 m intervals. Symbols as follows: crosses, permanent stations maintained by ERI; diamond, Mt. Fuji summit Weather Station maintained since 1987 by JMA; and open circles, stations maintained by NIED. Stations FJH, FJN, FJS and FJY have borehole tiltmeters and 3-component short-period seismometers installed at 200 m depth. (inset map) Tectonic map, with solid lines indicating Eurasian (EUR), N American (NAM) and Philippine Sea (PHS) plate boundaries. Taken from Nakamichi and others, 2004.

The Fuji DLF earthquake epicenters were located using 1987 to 2001 data from the early 1980 Kanto-Tokai seismic network and later data taken at the four Fuji stations installed in 1990 (figure 3). Nakamichi and others (2005) reexamined epicenter locations of Ukawa (2004). JMA updated safety and evacuation plans.

Figure (see Caption) Figure 3. Cumulative number of DLF events (dotted curve) at Fuji during 1980-2004 and their cumulative wave energy (solid line). Note new instruments and processing accounted for some of the increase seen in 2000-2001 (right of the vertical line), however there was a clear marked increase in events there. After Ukawa (2005).

DLFs during 2000-2001. Ukawa (2005) examined the 2000-2001 DLF swarm beneath Fuji. The typical activity here since the early 1980s was 10-20 earthquakes a year at midcrustal depth described as burst-like activity lasting from several minutes to 30 minutes.

The cumulative occurrence of DLF earthquakes their associated cumulative wave energy are plotted in figure FUJ2. The cumulative number rate, or the slope of the curve, is almost constant between 1980-1995, followed by several small slope changes before the later months of 2000 due to the improvements in the seismic network and the new data processing system. The sharp increase in 2000-2001 is far larger than the increase due to the enlarged seismic network. In total, 286 events were identified during the eight months from October 2000 to May 2001. The wave energy increased to approximately twice the average recorded during the prior years.

Regarding Fuji, Ukawa (2005) notes, "On the basis of the DLF earthquake observations by the NIED seismic network, we investigated the temporal change of their occurrence rate from 1980 to 2003 and the hypocenter locations from 1987 to May 2001. The occurrence rate and the seismic wave energy release rate show an abrupt increase from October 2000 to May 2001, suggesting a change in the environment. ...Relocation of hypocenters of the DLF earthquakes indicates that hypocenters of the DLF earthquakes cluster mainly in an elongated region measuring 5 km along the long axis in a NW-SE direction, the center of which is located about 3 km NE from the summit. In addition to the main cluster, hypocenters extend to the southwest from the summit. During the swarm activity in 2000 to 2001, activity in the primary hypocenter region on the northeastern side of Mount Fuji increased greatly. The focal depths of well located DLF events range from 10 to 20 km. The sharp increase of DLF earthquake activity at Mount Fuji began soon after magma discharge and intrusion events in the Miyake-jima and Kozu-shima region in July and August 2000. These events may have modified the state of the deep magmatic system beneath Mount Fuji, thus triggering the DLF earthquake swarm."

Figure 4 shows the three volcanoes mentioned above: Fuji, Miyake-jima, and Kozu-shima. Several more volcanoes also of Holocene age did not erupt.

Figure (see Caption) Figure 4. Ukawa (2005) noted the 2000-2001 DLF swarm beneath Fuji occurred soon after the July-August 2000 magma discharge and intrusion events located at Kozu-shima and Miyake-jima. Those two volcanoes are located in the Pacific ~135 km from Fuji. Fuji did not erupt. The yellow triangles show locations of other Holocene volcanoes listed in the GVP database. Like Fuji, these also did not erupt. Base map courtesy of the Microsoft Corporation with labels by BGVN editors.

MLF earthquakes during 1998-2003. Nakamichi and others (2004) revisited Fuji MLF data, that like the DLFs of 2000-2001, they also clustered near the summit. "We have determined the hypocenter locations of MLFs using the hypoDD program [a double-difference algorithm; Waldhauser and Ellsworth, 2000] and repicked arrival times from the seismic networks of ERI, JMA and NIED in and around Mt. Fuji between 1998 and 2003 including the active periods from September 2000 to May 2001, [figure 5]".

Figure (see Caption) Figure 5. Comparison between the Fuji hypocenters of the MLFs by Nakamichi and others (2004) (red circles) and the routine processing at NIED (black circles). (a) Map view of hypocenters, (b) E-W cross-section, and (c) N-S cross-section. Taken from Nakamichi and others (2004).

The authors summarized their results as follows: "(1) Hypocenters of MLFs define an ellipsoidal volume, 5 km in diameter ranging from 11 to 16 km in focal depth. (2) This volume is centered at 3 km NE of the summit and its long axis is trending NW. This orientation coincides with the major axis of tectonic compression around Mt. Fuji. (3) The center of the MLF epicenters migrated upward and 2-3 km from SE to NW in 1998-2001."

Nakamichi and others, (2004) continue, "We interpret that the hypocentral migration of MLFs reflects magma movement associated with a NW-SE oriented dike beneath Mt. Fuji, figure 6. The relative error ranges of the hypocenters relocated here are from 100 to 500 m horizontally and from 200 to 700 m vertically. No elongated structure in the direction of the observed NW- SE strike is observed in the simulations, indicating that the observed strike is not an artifact of the relocation procedure [seen in Figure 6b along the plane A-A']. The extent of this depth range is also supported by the spread in S-P readings for individual earthquakes. S-P arrival time differences for well-recorded MLFs at station KMR range from 1.9 to 2.4 s, verifying that MLFs beneath Mt. Fuji span a depth range of at least 4 km, and are not confined to a very small volume."

Figure (see Caption) Figure 6. Hypocentral distributions of the Fuji MLFs, as determined by the hypoDD program. (a) Map view of relocated hypocenters. Hypocenters at the intersection of A-A' with B-B' shown enlarged as a circle above and to the right. (b) Cross-section A-A'. (c) Cross-section B-B'. Cross-sections A-A' and B-B' include earthquake hypocenters projected from up to 10 km on either side of the cross section line. Taken from Nakamichi and others, 2004.

The MLFs also shifted with time. The spatial and temporal variations of MLF hypocenters plotted on figure 7. Nakamichi and others (2004) observed focal depths of MLFs in 1998- 1999 that were 12-16 km deep and "seemed to move deeper gradually."

Figure (see Caption) Figure 7. Spatial and temporal variations of the Fuji hypocenters of 1998-2003 MLFs. Top plot records distances from hypocenters on the NW-SE horizontal plane projected to zero on the line A-A' of Figure 6. Bottom plot records focal depths vs. time projected to the vertical plane through A-A'. Some or all these variations were interpreted as a manifestation of magma recharge and migration. Nakamichi and others, 2004.

Two key points from Nakamichi and others (2004) were (1) the MLF processing indicated that the hypocenters migrated 2-3 km upward during 1998-2001, and (2) they interpreted the MLF hypocenter migration as reflecting magma movement associated with a NW-trending dike beneath Fuji.

2011 Fuji stress change after the MW 9 Tohoko earthquake. Fujita and others (2013) studied the Tohoko earthquake and aftershocks in order to see whether the changes in the stress field and pressure changes would cause the known active magma system to erupt. The Tohoku earthquake, MW~9, struck on 11 Mar 2011. Extension occurred over a wide region of the Japanese mainland (Fujita and others, 2013). Aftershocks included those at N Nagano (MW 6.3) on 12 March, at E Shizoka (MW 5.9) on 15 March, and at N Ibaraki (MW 5.8) on 19 March, figure 8. The E Shizuoka aftershock struck beneath Fuji's S flank above its magma system. Fujita and others (2013) selected parameters of the two highest magnitude Tohoko earthquakes from Ozawa et al. (2011) plus the E. Shizuoka earthquake to investigate the change below Fuji. Using seismic data and later modeling they found the change in static pressure below Fuji insufficient to cause an eruption.

Figure (see Caption) Figure 8. A map showing Fuji on Honshu Island with a 500 x 200 km box enclosing the epicenters in the main sequence of the Tohoko megathrust earthquake. Epicenters of key aftershocks are shown as blue stars and one green star. The later struck 15 March, 4 days after the main event at 7-12 km depth below Fuji. After Fujita and others, 2013.

The fault parameters of the Tohoko earthquakes (Table 3) were estimated by Ozawa and others (2011). With regard to the E Shizouka earthquake, Fujita and others (2013) determined the East Shizuoka source fault using the method of Ueda and others (2005) and "determined the best-fit fault model to be almost strike-slip with some reverse components, located a few kilometers south of the summit trending from depths of 7-12 km." Note that on table 3 the "Depth (top)" value of 7 km locates the top of the fault.

Table 3. Fault parameters computed for two of the strongest Tohoku earthquakes and the E Shizuoka aftershock. Tohoku parameters are from Ozawa and others (2011); those for the E Shizuoka were obtained by applying the method of Ueda and others (2005). Taken from Fujita and others (2013).

Parameters Tohoku 1 Tohoku 2 East Shizuoka
Latitude 38.80°N 37.33°N 35.3161°N
Longitude 144.00°E 142.80°E 138.7130°E
Depth (top), km 5.1 17 7
Length, km 186 194 6
Width, km 129 88 8
Strike, degrees 203 203 24
Dip, degrees 16 15 80
Rake, degrees 101 83 20
Dislocation, m 24.7 6.1 0.86
Magnitude 8.8 8.3 6.0

Figure 9 shows the distribution of hypocenters of both tectonic (blue) and DLP (red) earthquakes during 1996-2011. Tectonic earthquakes occurring during 1996-2011 (blue circles) cluster to the S at ~5-15 km depth and NE from ~17 km deep to below the 25 km scale limit with little temporal change in number until a detectable rate rise in early 2011. Hypocenters of DLFs occurring during 1996-2011 (red circles) cluster nearest the crater N at ~10-15 km depth with little temporal change in number until a detectable rate rise in early 2011. The largest event shown, the E Shizuoka tectonic earthquake (15 March 2011) occurred on the S flank of Mount Fuji at a depth of 12 km (table 3 lists the top of the fault at 7 km). Remote aftershocks were centered a few kilometers N of the summit. Taken from Fujita and others (2013).

Figure (see Caption) Figure 9. Mt Fuji summit, yellow triangle, shown with tectonic and DLF earthquakes during 1996 to 2011. Red circles correspond to hypocenters of Deep Long Period (DLP) events, and blue circles correspond to tectonic earthquakes. Note the DLP increase in 2000 and 2001, shortly after the Miyake-jima volcano eruption and huge ground deformation on Izu peninsula ~100 km SE of Mount Fuji. Courtesy of Fujita and others (2013).

The relocated hypocenters computed by Fujita and others (2013) compared to the hypocenters of the same events routinely obtained by NIED (Ukawa, 2001), showed improvement in location accuracy (figure 10). The hypocenters by NIED are distributed in a larger volume and not along a particular plane while in this study they are much more concentrated and trending NNE. As seen on figure FUJ 9, Fujita and others (2013) noted "The dislocation was 86 cm toward the NNE with a strike of 240, dip of 800, and rake of 200." Aftershocks of the E Shizouka earthquake also occurred along this fault."

Figure (see Caption) Figure 10. Topographic station location map of Fuji showing an estimated dislocation of 86 cm along a 6x6 km fault plane based on GPS data from NIED and Graphical Survey Institute (GEONET) data. Observed (red) and calculated (blue) displacement vectors are shown. Courtesy of Fujita and others (2013).

The static stress change caused by the E Shizouka earthquake was on the order of 0.1-1 MPa, or 0.2%, at the boundary of the magma reservoir, which was theoretically sufficient to trigger an eruption (Walter and others 1997; Walter and others 2009).

The deformation of Fuji's magma system was based on finite-element modeling of the Japanese mainland and Fuji seismic tomography. At Fuji, the stress changes to the magma reservoir were on the order of 0.001-0.01 MPa for the Tohoku earthquake and 0.1-1 MPa for the East Shizuoka earthquake (Fujita and others, 2013). Were these static stress changes sufficient to promote new fractures at the magma reservoir wall and magma injection? Fujita and others, 2013 maintain, "This is less than the magnitude required to break new faults but could trigger some perturbation in unstable faults or in the hydrothermal and magmatic systems. However, the magma beneath Mount Fuji does not seem to have enough potential to erupt at this moment".

References. Fujita, E., Kozono, T., Ueda, H., Kohno, Y., Yoshioka, S., Toda, N., Kikuchi, A., and Ida, Y. 2013, Stress field change around the Mount Fuji volcano magma system caused by the Tohoku megathrust earthquake, Japan. Bulletin of Volcanology, 75(1), 1-14.

Koyama M., 2002, Mechanical coupling between volcanic unrests and large earthquakes: a review of examples and mechanics. J Geogr 111:222-232, in Japanese with English abstract.

Koyama M., 2007, Database of eruptions and other activities of Fuji Volcano, Japan, based on historical records since AD 781. Yamanashi Institute of Environmental Sciences, Fuji Volcano, pp 119- 136, in Japanese with English abstract.

Nakamichi H., Ukawa, M., Sakai S., 2004, Precise hypocenter locations of midcrustal low-frequency earthquakes beneath Mt. Fuji, Japan, Earth, Planets and Space, 56, e37-e4.

Nakamichi, H., Hamaguchi , H. Tanaka S., Ueki S., Nishimura T., Hasegawa A., 2003, Source mechanisms of deep and intermediate-depth low frequency earthquakes beneath Iwate volcano, northeastern Japan, Geophysical Journal International, 154, 811-828.

Nishimura T., Ozawa S., Murakami M., Sagiya T., Tada T., Kaidzu M., Ukawa M., 2001, Crustal deformation caused by magma migration in the northern Izu Islands, Japan. Geophysical Research Letters 28:3745-3748.

Ozawa S., Nishimura T., Suito H., Kobayashi T., Tobita M., Imakiire T., 2011, Coseismic and postseismic slip of the 2011 magnitude-9 Tohoku-Oki earthquake. Nature 475:373-377.

Ueda H., Fujita E., Ukawa M., Yamamoto E., Irawan M., Kimata F., 2005, Magma intrusion and discharge process at the initial stage of the 2000 activity of Miyakejima, Central Japan, inferred from tilt and GPS data. Geophysical Journal International 161:891-906.

Ukawa, M., 2005, Deep low-frequency earthquake swarm in the mid crust beneath Mount Fuji (Japan) in 2000 and 2001, Bulletin of Volcanology, 68 (2005), pp. 47-56.

Waldhauser, F. and W. L. Ellsworth, 2000, A double-difference earthquake location algorithm: Method and application to the northern Hayward fault, California, Bull. Seismol. Soc. Am., 90, 1353-1368.

Walter T., 2007, How a tectonic earthquake may wake up volcanoes: stress transfer during the 1996 earthquake-eruption sequence at the Karymsky Volcanic Group, Kamchatka. Earth and Planetary Science Letters 264:347-359.

Walter T., Amelung F., 2007, Volcanic eruptions following M≥9 megathrust earthquakes: implications for the Sumatra-Andaman volcanoes. Geology 35:539-542.

Walter, T., Wang, R., Zimmer, M., Grosser, H., Luhr, B., and Ratdomopurubo, A., 2007, Volcanic activity influenced by tectonic earthquake: static and dynamic stress triggering at Mt. Merapi. Geophysical Research Letters 34:L05304.

Walter, T., Wang, R., Acocella, V., Neri, M., Grosser, H., and Zschau, J., 2009, Simultaneous magma and gas eruptions at three volcanoes in southern Italy: an earthquake trigger? Geology 37:251-254.

Information Contacts: National Research Institute for Earth Science and Disaster Prevention (NIED), 3-1 Tennodai, Tsukuba-shi, Ibaraki-ken, 305, Japan (URL: http://www.bosai.go.jp); Japan Meteorological Agency (JMA), Volcanological Division, 1-3-4 Ote-machi, Chiyoda-ku, Tokyo 100, Japan (URL: http://www.jma.go.jp/); Volcano Research Center, Earthquake Research Institute (ERI), University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-0032, Japan (URL: http://www.eri.u-tokyo.ac.jp/VRC/index_E.html).

This compilation of synonyms and subsidiary features may not be comprehensive. Features are organized into four major categories: Cones, Craters, Domes, and Thermal Features. Synonyms of features appear indented below the primary name. In some cases additional feature type, elevation, or location details are provided.

Eruptive History

There is data available for 58 confirmed Holocene eruptive periods.

[ 1854 Dec 23 - 1855 Jan 9 ] Uncertain Eruption

Episode 1 | Eruption Episode
1854 Dec 23 - 1855 Jan 9 Evidence from Unknown

List of 1 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Earthquake (tectonic) Before eruption.

[ 1770 Sep 16 ] Uncertain Eruption

Episode 1 | Eruption Episode South flank?
1770 Sep 16 - Unknown Evidence from Unknown

List of 3 Events for Episode 1 at South flank?

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion Uncertain
   - - - -    - - - - Lava flow Uncertain
   - - - -    - - - - Cinder Cone Uncertain

[ 1708 Dec - 1709 Jan 16 (?) ] Uncertain Eruption

Episode 1 | Eruption Episode
1708 Dec - 1709 Jan 16 (?) Evidence from Unknown

List of 1 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion Uncertain

1707 Dec 16 - 1708 Feb 24 (?) Confirmed Eruption Max VEI: 5

Episode 1 | Eruption Episode SE flank (Hoei Craters)
1707 Dec 16 - 1708 Feb 24 (?) Evidence from Observations: Reported

List of 14 Events for Episode 1 at SE flank (Hoei Craters)

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Ash
   - - - -    - - - - Lapilli
   - - - -    - - - - Bombs
   - - - -    - - - - Pumice
   - - - -    - - - - Lightning
   - - - -    - - - - Earthquakes (undefined) Before. Small.
   - - - -    - - - - Earthquakes (undefined)
   - - - -    - - - - Lahar or Mudflow
   - - - -    - - - - Fauna Kill Terrestrial.
   - - - -    - - - - Property Damage
   - - - -    - - - - Evacuations
1707 Dec 16    - - - - VEI (Explosivity Index)
1708    - - - - Fatalities

1700 Confirmed Eruption Max VEI: 2 (?)

Episode 1 | Eruption Episode
1700 - Unknown Evidence from Observations: Reported

List of 1 Events for Episode 1

Start Date End Date Event Type Event Remarks
1700    - - - - VEI (Explosivity Index)

[ 1627 ] Uncertain Eruption

Episode 1 | Eruption Episode
1627 - Unknown Evidence from Unknown

[ 1560 Jan 4 ] Uncertain Eruption

Episode 1 | Eruption Episode
1560 Jan 4 - Unknown Evidence from Unknown

List of 1 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Lahar or Mudflow

1511 Sep 1 ± 30 days Confirmed Eruption Max VEI: 2 (?)

Episode 1 | Eruption Episode
1511 Sep 1 ± 30 days - Unknown Evidence from Observations: Reported

List of 2 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Lava flow
1511 Sep 1 ± 30 days    - - - - VEI (Explosivity Index)

1435 Dec 31 ± 60 days Confirmed Eruption Max VEI: 2 (?)

Episode 1 | Eruption Episode North flank (Onagare lava?)
1435 Dec 31 ± 60 days - Unknown Evidence from Observations: Reported

List of 4 Events for Episode 1 at North flank (Onagare lava?)

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Lava flow
   - - - -    - - - - Scoria
1435 Dec 31 ± 60 days    - - - - VEI (Explosivity Index)

[ 1427 Jun 28 ] Uncertain Eruption

Episode 1 | Eruption Episode
1427 Jun 28 - Unknown Evidence from Unknown

List of 1 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion Uncertain

1083 Apr 17 Confirmed Eruption Max VEI: 2 (?)

Episode 1 | Eruption Episode
1083 Apr 17 - Unknown Evidence from Observations: Reported

List of 1 Events for Episode 1

Start Date End Date Event Type Event Remarks
1083 Apr 17    - - - - VEI (Explosivity Index)

1033 Jan 19 (?) Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode Summit, SSE flank (Nishi-Asakizuka)
1033 Jan 19 (?) - Unknown Evidence from Observations: Reported

List of 3 Events for Episode 1 at Summit, SSE flank (Nishi-Asakizuka)

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Lava flow
1033 Jan 19
(?)
   - - - - VEI (Explosivity Index)

[ 1017 Oct 1 ± 30 days ] Uncertain Eruption

Episode 1 | Eruption Episode North flank
1017 Oct 1 ± 30 days - Unknown Evidence from Unknown

0999 Mar Confirmed Eruption Max VEI: 2 (?)

Episode 1 | Eruption Episode South flank ?
0999 Mar - Unknown Evidence from Observations: Reported

List of 3 Events for Episode 1 at South flank ?

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion Uncertain
   - - - -    - - - - Lava flow Uncertain
0999 Mar    - - - - VEI (Explosivity Index)

[ 0993 Sep 1 ± 30 days ] Uncertain Eruption

Episode 1 | Eruption Episode
0993 Sep 1 ± 30 days - Unknown Evidence from Unknown

List of 1 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Audible Sounds

[ 0952 Mar (?) ] Uncertain Eruption

Episode 1 | Eruption Episode NE flank
0952 Mar (?) - Unknown Evidence from Unknown

0937 Dec 18 Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode North flank (Kenmarubi II?)
0937 Dec 18 - Unknown Evidence from Observations: Reported

List of 3 Events for Episode 1 at North flank (Kenmarubi II?)

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Lava flow
0937 Dec 18    - - - - VEI (Explosivity Index)

0932 Nov 19 Confirmed Eruption Max VEI: 2 (?)

Episode 1 | Eruption Episode North flank (Kenmarubi I)
0932 Nov 19 - Unknown Evidence from Observations: Reported

List of 4 Events for Episode 1 at North flank (Kenmarubi I)

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Lava flow
   - - - -    - - - - Property Damage
0932 Nov 19    - - - - VEI (Explosivity Index)

0870 Aug Confirmed Eruption Max VEI: 2 (?)

Episode 1 | Eruption Episode
0870 Aug - Unknown Evidence from Observations: Reported

List of 2 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
0870 Aug    - - - - VEI (Explosivity Index)

0864 Jun 12 (?) - 0866 Feb 1 ± 30 days Confirmed Eruption Max VEI: 3

Episode 1 | Eruption Episode NW flank (Nagao-yama, Kudari-yama)
0864 Jun 12 (?) - 0866 Feb 1 ± 30 days Evidence from Observations: Reported

List of 7 Events for Episode 1 at NW flank (Nagao-yama, Kudari-yama)

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Lava flow
   - - - -    - - - - Earthquakes (undefined)
   - - - -    - - - - Fauna Kill Aquatic.
   - - - -    - - - - Fauna Kill Terrestrial.
   - - - -    - - - - Property Damage
0864 Jun 12
(?)
   - - - - VEI (Explosivity Index)

0830 Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode NW flank (Koriana)
0830 - Unknown Evidence from Observations: Reported

List of 3 Events for Episode 1 at NW flank (Koriana)

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Lava flow
0830    - - - - VEI (Explosivity Index)

0826 Dec 31 ± 30 days Confirmed Eruption Max VEI: 2 (?)

Episode 1 | Eruption Episode
0826 Dec 31 ± 30 days - Unknown Evidence from Observations: Reported

List of 2 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion Uncertain
0826 Dec 31 ± 30 days    - - - - VEI (Explosivity Index)

0800 Apr 11 - 0802 Feb 6 (in or after) Confirmed Eruption Max VEI: 4

Episode 1 | Eruption Episode Summit, NE and NW flanks (Tenjin-yama)
0800 Apr 11 - 0802 Feb 6 (in or after) Evidence from Observations: Reported

List of 6 Events for Episode 1 at Summit, NE and NW flanks (Tenjin-yama)

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Lava flow
   - - - -    - - - - Cinder Cone
   - - - -    - - - - Ash
   - - - -    - - - - Property Damage
0800 Apr 11    - - - - VEI (Explosivity Index)

0781 Jul - 0781 Jul Confirmed Eruption Max VEI: 3

Episode 1 | Eruption Episode
0781 Jul - 0781 Jul Evidence from Observations: Reported

List of 3 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Ash
0781 Jul    - - - - VEI (Explosivity Index)

0720 ± 100 years Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode NW flank (Kori-ike, Hakudairyuo)
0720 ± 100 years - Unknown Evidence from Isotopic: 14C (uncalibrated)

List of 4 Events for Episode 1 at NW flank (Kori-ike, Hakudairyuo)

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Lava flow
   - - - -    - - - - Scoria
0720 ± 100 years    - - - - VEI (Explosivity Index)

0530 (?) Confirmed Eruption Max VEI: 3

Episode 1 | Eruption Episode South flank (Takabachi)
0530 (?) - Unknown Evidence from Correlation: Tephrochronology

List of 3 Events for Episode 1 at South flank (Takabachi)

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Lava flow
0530
(?)
   - - - - VEI (Explosivity Index)

0520 ± 100 years Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode SE flank (Makuiwa, Nishi-Futatsuzuka)
0520 ± 100 years - Unknown Evidence from Isotopic: 14C (uncalibrated)

List of 3 Events for Episode 1 at SE flank (Makuiwa, Nishi-Futatsuzuka)

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Lava flow
0520 ± 100 years    - - - - VEI (Explosivity Index)

0470 ± 100 years Confirmed Eruption Max VEI: 3 (?)

Episode 1 | Eruption Episode SE flank (Kita-Kansu-yama)
0470 ± 100 years - Unknown Evidence from Isotopic: 14C (uncalibrated)

List of 3 Events for Episode 1 at SE flank (Kita-Kansu-yama)

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Scoria
0470 ± 100 years    - - - - VEI (Explosivity Index)

0400 (?) Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode SE flank (Akatsuka)
0400 (?) - Unknown Evidence from Correlation: Tephrochronology

List of 3 Events for Episode 1 at SE flank (Akatsuka)

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Lava flow
0400
(?)
   - - - - VEI (Explosivity Index)

0370 ± 200 years Confirmed Eruption  

Episode 1 | Eruption Episode SSE flank (Obuchi Craters)
0370 ± 200 years - Unknown Evidence from Isotopic: 14C (uncalibrated)

List of 3 Events for Episode 1 at SSE flank (Obuchi Craters)

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Lava flow
   - - - -    - - - - Scoria

0350 ± 300 years Confirmed Eruption Max VEI: 3

Episode 1 | Eruption Episode SE flank (Kurotsuka)
0350 ± 300 years - Unknown Evidence from Isotopic: 14C (uncalibrated)

List of 3 Events for Episode 1 at SE flank (Kurotsuka)

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Lava flow
0350 ± 300 years    - - - - VEI (Explosivity Index)

0300 (?) Confirmed Eruption Max VEI: 1

Episode 1 | Eruption Episode NW flank (Oniwa-Okuniwa)
0300 (?) - Unknown Evidence from Correlation: Tephrochronology

List of 3 Events for Episode 1 at NW flank (Oniwa-Okuniwa)

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Lava flow
0300
(?)
   - - - - VEI (Explosivity Index)

0250 (?) Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode NW flank (Kita-Koriike)
0250 (?) - Unknown Evidence from Correlation: Tephrochronology

List of 2 Events for Episode 1 at NW flank (Kita-Koriike)

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
0250
(?)
   - - - - VEI (Explosivity Index)

0240 ± 150 years Confirmed Eruption  

Episode 1 | Eruption Episode SE flank, Tephra layer S-24-2
0240 ± 150 years - Unknown Evidence from Isotopic: 14C (uncalibrated)

List of 3 Events for Episode 1 at SE flank, Tephra layer S-24-2

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Pyroclastic flow Uncertain
   - - - -    - - - - Lahar or Mudflow Uncertain

0220 (?) Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode NE flank (Hinokimarubi lava flow)
0220 (?) - Unknown Evidence from Correlation: Tephrochronology

List of 3 Events for Episode 1 at NE flank (Hinokimarubi lava flow)

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Lava flow
0220
(?)
   - - - - VEI (Explosivity Index)

0200 (?) Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode NW flank (Sajiki-yama)
0200 (?) - Unknown Evidence from Correlation: Tephrochronology

List of 2 Events for Episode 1 at NW flank (Sajiki-yama)

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
0200
(?)
   - - - - VEI (Explosivity Index)

0100 (?) Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode NW flank (Ohira-yama)
0100 (?) - Unknown Evidence from Correlation: Tephrochronology

List of 2 Events for Episode 1 at NW flank (Ohira-yama)

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
0100
(?)
   - - - - VEI (Explosivity Index)

0050 (?) Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode NW flank (Futatsuzuka)
0050 (?) - Unknown Evidence from Correlation: Tephrochronology

List of 2 Events for Episode 1 at NW flank (Futatsuzuka)

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
0050
(?)
   - - - - VEI (Explosivity Index)

0100 BCE ± 150 years Confirmed Eruption  

Episode 1 | Eruption Episode South flank
0100 BCE ± 150 years - Unknown Evidence from Isotopic: 14C (uncalibrated)

List of 2 Events for Episode 1 at South flank

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Lava flow

0190 BCE ± 100 years Confirmed Eruption  

Episode 1 | Eruption Episode Tephra layer Yu-2
0190 BCE ± 100 years - Unknown Evidence from Correlation: Tephrochronology

List of 2 Events for Episode 1 at Tephra layer Yu-2

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Scoria

0520 BCE ± 300 years Confirmed Eruption  

Episode 1 | Eruption Episode Tephra layer S-18
0520 BCE ± 300 years - Unknown Evidence from Isotopic: 14C (calibrated)

List of 3 Events for Episode 1 at Tephra layer S-18

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Avalanche
   - - - -    - - - - Edifice Destroyed Collapse/avalanche

0780 BCE ± 500 years Confirmed Eruption  

Episode 1 | Eruption Episode Tephra layer SPY4
0780 BCE ± 500 years - Unknown Evidence from Isotopic: 14C (calibrated)

List of 2 Events for Episode 1 at Tephra layer SPY4

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Pyroclastic flow

0930 BCE (after) Confirmed Eruption Max VEI: 5

Episode 1 | Eruption Episode Upper SE flank, Tephra layer Zu
0930 BCE (after) - Unknown Evidence from Isotopic: 14C (uncalibrated)

List of 3 Events for Episode 1 at Upper SE flank, Tephra layer Zu

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Scoria
0930 BCE
(after)
   - - - - VEI (Explosivity Index)

1010 BCE ± 100 years Confirmed Eruption  

Episode 1 | Eruption Episode Tephra unit SYP3
1010 BCE ± 100 years - Unknown Evidence from Isotopic: 14C (calibrated)

List of 5 Events for Episode 1 at Tephra unit SYP3

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Pyroclastic flow
   - - - -    - - - - Ash
   - - - -    - - - - Bombs
   - - - -    - - - - Scoria

1030 BCE (?) Confirmed Eruption Max VEI: 4

Episode 1 | Eruption Episode NW flank (Omuro-yama)
1030 BCE (?) - Unknown Evidence from Correlation: Tephrochronology

List of 4 Events for Episode 1 at NW flank (Omuro-yama)

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Lava flow
   - - - -    - - - - Scoria
1030 BCE
(?)
   - - - - VEI (Explosivity Index)

1300 BCE ± 150 years Confirmed Eruption  

Episode 1 | Eruption Episode Tephra unit SYP2
1300 BCE ± 150 years - Unknown Evidence from Isotopic: 14C (calibrated)

List of 5 Events for Episode 1 at Tephra unit SYP2

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Pyroclastic flow
   - - - -    - - - - Ash
   - - - -    - - - - Bombs
   - - - -    - - - - Scoria

1350 BCE (?) Confirmed Eruption Max VEI: 5

Episode 1 | Eruption Episode Tephra layer Os
1350 BCE (?) - Unknown Evidence from Correlation: Tephrochronology

List of 3 Events for Episode 1 at Tephra layer Os

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Scoria
1350 BCE
(?)
   - - - - VEI (Explosivity Index)

1450 BCE ± 100 years Confirmed Eruption  

Episode 1 | Eruption Episode Tephra layer S-10
1450 BCE ± 100 years - Unknown Evidence from Correlation: Tephrochronology

List of 2 Events for Episode 1 at Tephra layer S-10

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Scoria

1510 BCE ± 100 years Confirmed Eruption  

Episode 1 | Eruption Episode Tephra unit SYP1
1510 BCE ± 100 years - Unknown Evidence from Isotopic: 14C (calibrated)

List of 5 Events for Episode 1 at Tephra unit SYP1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Pyroclastic flow
   - - - -    - - - - Ash
   - - - -    - - - - Bombs
   - - - -    - - - - Scoria

1850 BCE ± 150 years Confirmed Eruption  

Episode 1 | Eruption Episode
1850 BCE ± 150 years - Unknown Evidence from Isotopic: 14C (uncalibrated)

List of 3 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Pyroclastic flow
   - - - -    - - - - Lapilli

2050 BCE (?) Confirmed Eruption  

Episode 1 | Eruption Episode
2050 BCE (?) - Unknown Evidence from Isotopic: 14C (uncalibrated)

List of 2 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Pyroclastic flow

2450 BCE ± 500 years Confirmed Eruption  

Episode 1 | Eruption Episode Tephra layer SNG
2450 BCE ± 500 years - Unknown Evidence from Isotopic: 14C (uncalibrated)

List of 1 Events for Episode 1 at Tephra layer SNG

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion

2550 BCE (?) Confirmed Eruption  

Episode 1 | Eruption Episode Nihon-Land lava flow
2550 BCE (?) - Unknown Evidence from Correlation: Tephrochronology

List of 1 Events for Episode 1 at Nihon-Land lava flow

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Lava flow

2800 BCE ± 300 years Confirmed Eruption  

Episode 1 | Eruption Episode Tephra layer S-6
2800 BCE ± 300 years - Unknown Evidence from Correlation: Tephrochronology

List of 2 Events for Episode 1 at Tephra layer S-6

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Scoria

3050 BCE (?) Confirmed Eruption  

Episode 1 | Eruption Episode Tephra layer S-5
3050 BCE (?) - Unknown Evidence from Isotopic: 14C (uncalibrated)

List of 2 Events for Episode 1 at Tephra layer S-5

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Scoria

3690 BCE ± 100 years Confirmed Eruption  

Episode 1 | Eruption Episode
3690 BCE ± 100 years - Unknown Evidence from Isotopic: 14C (uncalibrated)

List of 1 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion

4120 BCE ± 300 years Confirmed Eruption  

Episode 1 | Eruption Episode Tephra layer S-0-6
4120 BCE ± 300 years - Unknown Evidence from Correlation: Tephrochronology

List of 1 Events for Episode 1 at Tephra layer S-0-6

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion

4730 BCE ± 500 years Confirmed Eruption  

Episode 1 | Eruption Episode Tephra layer S-0-5
4730 BCE ± 500 years - Unknown Evidence from Correlation: Tephrochronology

List of 1 Events for Episode 1 at Tephra layer S-0-5

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion

5070 BCE ± 200 years Confirmed Eruption  

Episode 1 | Eruption Episode Tephra layer I-7
5070 BCE ± 200 years - Unknown Evidence from Isotopic: 14C (uncalibrated)

List of 1 Events for Episode 1 at Tephra layer I-7

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion

5540 BCE ± 200 years Confirmed Eruption  

Episode 1 | Eruption Episode Tephra layer S-0-4
5540 BCE ± 200 years - Unknown Evidence from Isotopic: 14C (uncalibrated)

List of 1 Events for Episode 1 at Tephra layer S-0-4

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion

6050 BCE (?) Confirmed Eruption  

Episode 1 | Eruption Episode Nashigahara lava flow
6050 BCE (?) - Unknown Evidence from Correlation: Tephrochronology

List of 1 Events for Episode 1 at Nashigahara lava flow

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Lava flow

6240 BCE ± 300 years Confirmed Eruption  

Episode 1 | Eruption Episode Tephra layer S-0-3
6240 BCE ± 300 years - Unknown Evidence from Isotopic: 14C (uncalibrated)

List of 1 Events for Episode 1 at Tephra layer S-0-3

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion

6580 BCE (in or before) Confirmed Eruption  

Episode 1 | Eruption Episode Saruhashi and Shiraito lava flows
6580 BCE (in or before) - Unknown Evidence from Isotopic: 14C (uncalibrated)

List of 1 Events for Episode 1 at Saruhashi and Shiraito lava flows

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Lava flow violent, strong, or large

7310 BCE ± 500 years Confirmed Eruption  

Episode 1 | Eruption Episode Motomura-yama lava flow
7310 BCE ± 500 years - Unknown Evidence from Isotopic: 14C (uncalibrated)

List of 1 Events for Episode 1 at Motomura-yama lava flow

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Lava flow

7530 BCE ± 300 years Confirmed Eruption  

Episode 1 | Eruption Episode Tephra layer S-0-2
7530 BCE ± 300 years - Unknown Evidence from Isotopic: 14C (uncalibrated)

List of 1 Events for Episode 1 at Tephra layer S-0-2

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion

7820 BCE ± 200 years Confirmed Eruption  

Episode 1 | Eruption Episode Tephra layer S-0-1
7820 BCE ± 200 years - Unknown Evidence from Isotopic: 14C (uncalibrated)

List of 1 Events for Episode 1 at Tephra layer S-0-1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion

8540 BCE (after) Confirmed Eruption  

Episode 1 | Eruption Episode South flank? (Mishima)
8540 BCE (after) - Unknown Evidence from Isotopic: 14C (uncalibrated)

List of 1 Events for Episode 1 at South flank? (Mishima)

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Lava flow
Deformation History

There is no Deformation History data available for Fujisan.

Emission History

There is no Emissions History data available for Fujisan.

Photo Gallery

Mount Fuji rises above mountains at the SW end of the Kanto plain in this view from Tokyo Tower. Significant ashfall impacted the ancient capital of Edo (Tokyo), 100 km to the NE, during the last eruption in 1707.

Photo by Richard Fiske, 1961 (Smithsonian Institution).
During summer the flanks Mount Fuji have oxidized scoria and lava flows visible above the timberline. The two “shoulders” on the lower flanks, in this view from the north near Lake Yamanaka, are remnants of a group of older volcanoes over which the modern symmetrical volcano was constructed. The shoulder to the left is a remnant of Kofuji (Old Fuji) volcano, and the broader shoulder to the right is a segment of Komitake, a mid-Pleistocene volcano.

Photo by Lee Siebert, 1970 (Smithsonian Institution).
Mount Fuji is a popular tourist destination, seen here providing the backdrop to a fireworks display at Lake Yamanaka, one of five lakes at the northern base of the volcano. The line of diagonal lights extending up the right-hand side of Fuji are mountain huts along the ten stations of the Fuji-Yoshida climbing route, the most popular of the six major summer ascent routes.

Photo by Lee Siebert, 1963 (Smithsonian Institution).
A contemporary folding screen by Ogata Korin correctly depicts the 1707 eruption of Mount Fuji that occured from the SE-flank Hoei crater (dark area at left); the ash plume is dispersing to the NE. The major explosive eruption was continuous during 16-20 December and intermittent until February 1708. Significant ashfall from this eruption reached the capital city of Edo (Tokyo). Secondary lahars damaged houses and agricultural land.

Photo by Chip Clark (Smithsonian Institution; courtesy of Robert Simmons).
Volcanic bombs ejected during the eruption of Mount Fuji in 1707 within light-colored tephra from the older Kofuji edifice. These blocks, about 30 cm in diameter, impacted the surface of the older tephra deposits near the rim of the 1707 Hoei crater. Erosion by strong winds removed the softer, hydrothermally altered tephra, leaving the blocks above the surface.

Photo by Lee Siebert, 1977 (Smithsonian Institution).
This entire flat forested plain, known as Aokigahara ("Blue Tree Plain") is underlain by a single massive lava flow from Fuji. A major explosive and effusive eruption began in June 864 CE from Nagaoyama, a vent on the NW flank. Lava flowed into lakes Motosu and Senoumi, destroying lakeshore houses. It divided Lake Senoumi into the two present-day lakes of Shojiko(seen here in the distance against a Tertiary mountain range to the NW) and Saiko. The Aokigahara Marubi lava field covered an area of 32 km2.

Photo by Lee Siebert, 1977 (Smithsonian Institution).
This lava flow on the shore of Saiko lake and the flat plain beyond it are part of a single massive lava flow erupted from Nagaoyama on the NW flank of Mount Fuji in 864 CE. The 32 km2 lava flow was responsible for the present morphology of Saiko lake, which formed when the lava flow split a former larger lake in two. The scoria cone on the horizon is Omuroyama, the largest flank cone of Mount Fuji, that formed during an eruption about 2,900 years ago.

Photo by Lee Siebert, 1977 (Smithsonian Institution).
Hikers peer into the 700-m-wide summit crater of Mount Fuji from its E rim. More than 100,000 people ascend its slopes yearly during the 2-month summer climbing season. A white meteorological observatory (upper right) sits at the summit, which is 240 m above the crater floor. A red oxidized scoria layer across the summit crater rim was emplaced about 2,100 years ago.

Photo by Lee Siebert, 1963 (Smithsonian Institution).
Fuji towers above Lake Yamanaka, one of the Fujigoko (the "Five Lakes of Fuji") that formed when lava flows blocked drainages against a Tertiary mountain range to the N. The smaller ridge at the snowline on the left is Hoeisan, a remant of Kofuji (Old Fuji), one of several older volcanoes above which the modern edifice was constructed.

Photo by Lee Siebert, 1970 (Smithsonian Institution).
Fuji contains a 700-m-wide crater at the summit of the modern cone that is constructed over a group of overlapping volcanoes. The diagonal line to the lower right is a road that extends to the timberline on the N flank.

Photo by Tom Pierson, 1995 (U.S. Geological Survey).
Fujisan towers above the major Tokyo-Osaka highway along the Pacific coast in southern Shizuoka Prefecture. Hoeisan is the smaller cone on the SE flank (to the right) and is a remant of Kofuji (Old Fuji), an ancestral volcano that preceded the construction of the modern edifice.

Photo by Ichio Moriya (Kanazawa University).
The large crater in the center of the photo was produced on the SE flank of Mount Fuji during the 1707-1708 eruption. This major explosive eruption ejected more than 1 km3 of tephra and resulted in ashfall in the capital city of Edo (Tokyo). Three craters were formed sequentially along a NW-SE-trend from the summit. The primary vent of the eruption was the upper crater (center), which is 750 x 1,500 m in size and 750 m deep from the highest point on the crater rim.

Photo by Ichio Moriya (Kanazawa University).
GVP Map Holdings

The maps shown below have been scanned from the GVP map archives and include the volcano on this page. Clicking on the small images will load the full 300 dpi map. Very small-scale maps (such as world maps) are not included. The maps database originated over 30 years ago, but was only recently updated and connected to our main database. We welcome users to tell us if they see incorrect information or other problems with the maps; please use the Contact GVP link at the bottom of the page to send us email.

Smithsonian Sample Collections Database

The following 28 samples associated with this volcano can be found in the Smithsonian's NMNH Department of Mineral Sciences collections, and may be availble for research (contact the Rock and Ore Collections Manager). Catalog number links will open a window with more information.

Catalog Number Sample Description Lava Source Collection Date
NMNH 101487 Unidentified -- --
NMNH 101488 Unidentified -- --
NMNH 101489 Unidentified -- --
NMNH 101490 Unidentified -- --
NMNH 108968 Olivine Basalt -- --
NMNH 108970 Olivine Basalt -- --
NMNH 112891 Olivine Basalt -- --
NMNH 112891 Olivine Basalt -- --
NMNH 112892 Olivine Basalt -- --
NMNH 112892 Olivine Basalt -- --
NMNH 112893 Olivine Basalt -- --
NMNH 112893 Olivine Basalt -- --
NMNH 112894 Andesite -- --
NMNH 112894 Andesite -- --
NMNH 112895 Dacitic Pumice -- --
NMNH 112895 Dacitic Pumice -- --
NMNH 112896 Basalt -- --
NMNH 112896 Basalt -- --
NMNH 112897 Olivine Basalt AOKIGAHARA LAVA --
NMNH 112897 Olivine Basalt AOKIGAHARA LAVA --
NMNH 113052 High-Alumina Basalt -- --
NMNH 113052 High-Alumina Basalt -- --
NMNH 113870 Olivine Basalt -- --
NMNH 113871 Olivine Basalt -- --
NMNH 113872-1 Olivine Basalt -- --
NMNH 113872-2 Olivine Basalt -- --
NMNH 61761 Basalt -- --
NMNH 92394 Lava -- --
External Sites