South Sarigan Seamount

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  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 16.58°N
  • 145.78°E

  • -184 m
    -604 ft

  • 284193
  • Latitude
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    Elevation

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Most Recent Bulletin Report: September 2014 (BGVN 39:09)


Studies reveal former summit removed and replaced by large crater due to the enigmatic May 2010 eruption

The last Bulletin report (BGVN 35:05) on South Sarigan Seamount was mistakenly catalogued under reports for Sarigan Island. In that report, a description of the 28-29 May 2010 eruption was discussed. Recently, Bulletin editors discovered that significant research has been completed concerning the South Sarigan Seamount’s 2010 eruption. In this Bulletin report, we will discuss some of that research.

This new research concluded that the South Sarigan Seamount is “part of a volcanic centre comprised of multiple cone edifices…” (Green and others, 2013). The northerly cone of this volcanic center is believed to be the source of the 2010 eruption, which was observed visually when an eruption plume, was seen rising from the ocean (Embley and others, 2013). The plume rose ~12 km through the atmosphere and was tracked by satellite. The Washington Volcanic Ash Advisory Center (VAAC) put out a report to inform the aviation community of the plume (Embley and others, 2013).

The 2010 eruption has been defined seismo-acoustically, and studied with multibeam and in situ sampling. It lasted ~3 days beginning on 27 May 2010. This eruption dramatically altered the northerly cone’s morphology, whose summit depth was initially ~184 m below sea level (Embley and others, 2013; Searcy, 2013). According to Embley and others (2013) the eruption led the formation of a breached crater, 350 m in diameter, and a substantial deposit on the W flank (figure 2). After the eruption, the crater floor dropped ~200 m beneath the pre-eruption summit (Embley and others, 2013).

Figure 2. (Top and bottom, respectively) Bathymetry from before and after the eruption rendered as colored relief for the inferred vent for the 2010 South Sarigan eruptions. View is from the W (note N arrow, and length and depth scales). As labeled, the 2002 image (top) and 2013 image (bottom) show the loss of summit material and the development of a summit crater. Portions of the rim appear intact from the earlier upper edifice, but a cleft resides on the rim’s W side. A zone of downslope deposits lies on this side of the edifice but is not identified on the image. The 2013 map was used to target dives with a JAMSTEC remotely operated vehicle in June 2013. This new information will help to better evaluate the hazard potential of submarine eruptions. Courtesy of NOAA PMEL.

 

Much of the research on the South Sarigan Seamount was completed as the result of research vessels (RVs) cruises, and submarine remotely operated vehicles (ROVs) observing and documenting the eruptive deposits and morphologic changes at the vent. Multibeam data was also collected. The findings have been chronicled in several papers, some of which are discussed here (Tamura and others, 2013; Embley and others, 2013; and Green and others, 2013).

Green and others (2013), Searcy (2013) and Snellen and others (2011) used various combinations of hydroacoustic, infrasound, and seismic signals to study the pace and phases of the eruption from a geophysical perspective. Green and others (2013) found that the eruption occurred in three stages, separated by three-hour periods of quiescence. In brief, these stages included “(1) A 46 h period during which broadband impulsive hydroacoustic signals were generated . . . [a total of] 7602 identified events . . .(2) a 5-hour period of 10 Hz hydroacoustic tremor, interspersed with large-amplitude, broadband signals…(3) An hour-long period of transient broadband events [that] culminated in two large-amplitude hydroacoustic events and one broadband infrasound signal.”

According to Green and others (2013), the first phase began at ~0241 UTC on 27 May 2010 when clustered hydroacoustic signals were detected by two hydroacoustic stations located on Wake Island and Queen Charlotte Islands. During this time, discolored water was also observed 8-11 km S of Sarigan Island. The second phase was detected at ~0330 UTC on 29 May with a near continuous tremor that lasted ~5 hours. The third phase, according to Green and others (2013) began at ~1137 UTC and at ~1209 UTC a distinctive tremor signal was detected. In addition to the seismic activity that occurred during the third phase, the ~12 km eruption plume was also generated.

Tamura and others (2013) noted a multibeam survey by R/V Melville conducted in early February 2013 over the unsurveyed main peak of South Sarigan Seamount volcanic center and over some of the previously surveyed peaks, enabling a comparison with the available older surveys. The older surveys consist of a 2002 survey by RV Ewing [EW0202] and a 2003 survey by RV Thompson [TN153] of the north peak where the 2010 eruption was believed to have taken place. Their comparisons show that downslope and W of the breach in the crater, a zone of positive depth changes of over 50 m occurs to ~2000 m depth on the volcano's flank. This is interpreted to be the deposit of material from the 2010 eruption together with part of the western flank that failed during the eruption. The volume of the downslope deposit is approximately twice as large as the amount of material lost from the summit. ROV dives on the volcano during 14-22 June 2013 showed that the northern wall of the crater appears to be “dominantly well-jointed andesite, with some interlayered basalt. No hydrothermal venting was observed in the crater, except weak shimmering water at the top of the crater wall.”

Embley and others (2013) employed an ROV to retrieve downslope samples, including pumice believed to have been associated with the 2010 eruption. The pumice collected was found to be andesitic in composition. Lava blocks, believed to be from older lava flows, were also sampled. Both the andesitic pumice and lava blocks contained similar weight percentages of SiO2 and MgO, while the pumice had a slightly higher weight percentage of K2O. Embley and others (2013) concluded that due to the abundance of andesite found in samples from the crater and the W flank deposit, both the older and the 2010 eruption of the South Sarigan Seamount were dominantly andesite in composition.

According to Embley and others (2013): “The South Sarigan event is one of the first instances of an explosive, relatively deep, submarine eruption that breached the surface ocean and for which we have quantitative data for the size and extent of the cratering event and deposits to match with seismic and hydroacoustic monitoring information. Submarine craters the size of the one formed during the eruption of South Sarigan are relatively common on seamounts along intra-oceanic arcs... This event, and a deeper and much larger event at Havre Seamount in the Kermadec arc in 2012 . . . underscores how little is known of the eruption history of most submarine arc volcanoes.”

References: Embley, R.W., Y. Tamura, S.G. Merle, T. Sato, O. Ishizuka, W.W. Chadwick Jr., D.A. Wiens, P. Shore, and R.J. Stern. 2014. Eruption of South Sarigan Seamount, Northern Mariana Islands: Insights into hazards from submarine volcanic eruptions. Oceanography 27(2):24–31, http://dx.doi.org/10.5670/oceanog.2014.37.

Green, D. N., Evers, L. G., Fee, D., Matoza, R. S., Snellen, M., Smets, P., & Simons, D., 2013, Hydroacoustic, infrasonic and seismic monitoring of the submarine eruptive activity and sub-aerial plume generation at South Sarigan, May 2010. Journal of Volcanology and Geothermal Research, 257, 31-43.

Searcy, C. 2013. Seismicity associated with the May 2010 eruption of South Sarigan Seamount, northern Mariana Islands. Seismological Research Letters 84(6):1,055–1,061, http://dx.doi.org/10.1785/0220120168

Snellen, M., Evers, L., and Simons, D. G. (2011). “Modeling the long-range acoustic propagation for the May 2010 Sarigan volcano eruption,” in Underwater Acoustics Measurements, edited by J. S. Papadakis (Kluwer, Kos, Greece), pp. 1361–1368

Tamura, Y.; Embley, R. W.; Nichols, A. R.; Ishizuka, O.; Merle, S. G.; Chadwick, B.; Stern, R. J.; Sato, T.; Wiens, D. A.; Shore, P., 2013, ROV Hyper-Dolphin Survey at the May 2010 Eruption Site on South Sarigan Seamount, Mariana Arc, Eos, Transactions of the American Geophysical Union [Paper presented at the 2013 Fall AGU Meeting], San Francisco, California, Abstract V31G-02

Information Contacts: Pacific Marine Environmental Laboratory, Ocean Environment Research Division, EOI Program, Hatfield Marine Science Center, 2115 S.E. OSU Dr., Newport, OR 97365.

The Global Volcanism Program has no Weekly Reports available for South Sarigan Seamount.

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.

05/2010 (BGVN 35:05) Sudden, short-lived, explosive eruption from submarine vent

09/2014 (BGVN 39:09) Studies reveal former summit removed and replaced by large crater due to the enigmatic May 2010 eruption




Bulletin Reports

All information contained in these reports is preliminary and subject to change.


05/2010 (BGVN 35:05) Sudden, short-lived, explosive eruption from submarine vent
Download or Cite this Report

According to a weekly USGS/CNMI Emergency Management Office (EMO) update on 4 June 2010, an explosive eruption from a submarine vent S of Sarigan Island occurred during 28-29 May 2010. The most energetic phase of the eruption, at 2147 on 29 May, lasted about 10 minutes based on seismic records from nearby Sarigan and Anatahan islands. The eruption sent an ash and gas cloud perhaps as high as 12.2 km altitude. Precursors included two moderate earthquakes and many smaller shocks; an earthquake of ~ M 4.8 accompanied the eruption. The plume drifted S, eventually passing over Guam (350 km SSW), but no fallout was reported there or on Saipan (165 km S).

Evidence of submarine volcanic activity was first observed late on 28 May during aerial observations by Juan Camacho, an EMO technician, who noted an elongate patch of discolored ocean water and possible light-colored floating debris about 8 km S of Sarigan Island. Alaska Volcano Observatory seismologists noted tremor on nearby seismic stations about the same time. Satellite image analysis by the National Weather Service in Guam indicated that the area of disturbance had grown significantly in size prior to the 29 May explosion. Within hours after the eruption, seismic activity began to decline, and after 31 May only a few scattered events were recorded.

The vent's exact location and depth remained uncertain. According to the USGS, the most likely source is the summit area of the South Sarigan seamount ~ 11 km S of Sarigan Island (figure 1). The summit of the conical structure lies at depths less than ~ 500 m below the surface.

Figure 1. Location map showing the volcanic islands of Sarigan and Anatahan, as well as the South and West Sarigan volcanic seamounts. Modified from Embley and Chadwick (2003).

A U.S. Fish and Wildlife Service research crew camped on Sarigan Island reported many felt earthquakes prior to the eruption. An explosion that sounded like thunder accompanied the event. They also heard increasing ocean wave activity during the night. Subsequently, a minor ashfall occurred.

The NOAA West Coast and Alaska Tsunami Warning Center reported that a 5-cm-high tsunami related to this event may have been recorded on a tide gauge in Saipan. According to a news article in the Saipan Tribune, the U.S. Fish and Wildlife evacuated 16 people, mostly scientists, from nearby islands, including eight people from Sarigan.

The USGS reported no evidence of volcanism after the 29 May eruption. Seismicity recorded by the nearest seismometer, on Sarigan Island, had returned to background levels. Nothing unusual was observed in satellite data.

Reference. Embley, B., and Chadwick, B., 2003, MR1 sonar provides new view of sea floor around Mariana Islands: NOAA Ocean Explorer, Submarine Ring of Fire 2003, 17 February 2003 (http://oceanexplorer.noaa.gov/explorations/03fire/logs/feb17/feb17.html).

Information Contacts: Emergency Management Office of the Commonwealth of the Northern Mariana Islands (EMO-CNMI) and USGS Hawaii Volcano Observatory, PO Box 100007, Saipan, MP 96950, USA (URL: http://www.cnmiemo.gov.mp/ and http://volcano.wr.usgs.gov/cnmistatus.php); NOAA Ocean Explorer, National Oceanic and Atmospheric Administration, U.S. Department of Commerce (URL: http://oceanexplorer.noaa.gov/explorations/03fire/logs/feb17/feb17.html).

09/2014 (BGVN 39:09) Studies reveal former summit removed and replaced by large crater due to the enigmatic May 2010 eruption
Download or Cite this Report

The last Bulletin report (BGVN 35:05) on South Sarigan Seamount was mistakenly catalogued under reports for Sarigan Island. In that report, a description of the 28-29 May 2010 eruption was discussed. Recently, Bulletin editors discovered that significant research has been completed concerning the South Sarigan Seamount’s 2010 eruption. In this Bulletin report, we will discuss some of that research.

This new research concluded that the South Sarigan Seamount is “part of a volcanic centre comprised of multiple cone edifices…” (Green and others, 2013). The northerly cone of this volcanic center is believed to be the source of the 2010 eruption, which was observed visually when an eruption plume, was seen rising from the ocean (Embley and others, 2013). The plume rose ~12 km through the atmosphere and was tracked by satellite. The Washington Volcanic Ash Advisory Center (VAAC) put out a report to inform the aviation community of the plume (Embley and others, 2013).

The 2010 eruption has been defined seismo-acoustically, and studied with multibeam and in situ sampling. It lasted ~3 days beginning on 27 May 2010. This eruption dramatically altered the northerly cone’s morphology, whose summit depth was initially ~184 m below sea level (Embley and others, 2013; Searcy, 2013). According to Embley and others (2013) the eruption led the formation of a breached crater, 350 m in diameter, and a substantial deposit on the W flank (figure 2). After the eruption, the crater floor dropped ~200 m beneath the pre-eruption summit (Embley and others, 2013).

Figure 2. (Top and bottom, respectively) Bathymetry from before and after the eruption rendered as colored relief for the inferred vent for the 2010 South Sarigan eruptions. View is from the W (note N arrow, and length and depth scales). As labeled, the 2002 image (top) and 2013 image (bottom) show the loss of summit material and the development of a summit crater. Portions of the rim appear intact from the earlier upper edifice, but a cleft resides on the rim’s W side. A zone of downslope deposits lies on this side of the edifice but is not identified on the image. The 2013 map was used to target dives with a JAMSTEC remotely operated vehicle in June 2013. This new information will help to better evaluate the hazard potential of submarine eruptions. Courtesy of NOAA PMEL.

 

Much of the research on the South Sarigan Seamount was completed as the result of research vessels (RVs) cruises, and submarine remotely operated vehicles (ROVs) observing and documenting the eruptive deposits and morphologic changes at the vent. Multibeam data was also collected. The findings have been chronicled in several papers, some of which are discussed here (Tamura and others, 2013; Embley and others, 2013; and Green and others, 2013).

Green and others (2013), Searcy (2013) and Snellen and others (2011) used various combinations of hydroacoustic, infrasound, and seismic signals to study the pace and phases of the eruption from a geophysical perspective. Green and others (2013) found that the eruption occurred in three stages, separated by three-hour periods of quiescence. In brief, these stages included “(1) A 46 h period during which broadband impulsive hydroacoustic signals were generated . . . [a total of] 7602 identified events . . .(2) a 5-hour period of 10 Hz hydroacoustic tremor, interspersed with large-amplitude, broadband signals…(3) An hour-long period of transient broadband events [that] culminated in two large-amplitude hydroacoustic events and one broadband infrasound signal.”

According to Green and others (2013), the first phase began at ~0241 UTC on 27 May 2010 when clustered hydroacoustic signals were detected by two hydroacoustic stations located on Wake Island and Queen Charlotte Islands. During this time, discolored water was also observed 8-11 km S of Sarigan Island. The second phase was detected at ~0330 UTC on 29 May with a near continuous tremor that lasted ~5 hours. The third phase, according to Green and others (2013) began at ~1137 UTC and at ~1209 UTC a distinctive tremor signal was detected. In addition to the seismic activity that occurred during the third phase, the ~12 km eruption plume was also generated.

Tamura and others (2013) noted a multibeam survey by R/V Melville conducted in early February 2013 over the unsurveyed main peak of South Sarigan Seamount volcanic center and over some of the previously surveyed peaks, enabling a comparison with the available older surveys. The older surveys consist of a 2002 survey by RV Ewing [EW0202] and a 2003 survey by RV Thompson [TN153] of the north peak where the 2010 eruption was believed to have taken place. Their comparisons show that downslope and W of the breach in the crater, a zone of positive depth changes of over 50 m occurs to ~2000 m depth on the volcano's flank. This is interpreted to be the deposit of material from the 2010 eruption together with part of the western flank that failed during the eruption. The volume of the downslope deposit is approximately twice as large as the amount of material lost from the summit. ROV dives on the volcano during 14-22 June 2013 showed that the northern wall of the crater appears to be “dominantly well-jointed andesite, with some interlayered basalt. No hydrothermal venting was observed in the crater, except weak shimmering water at the top of the crater wall.”

Embley and others (2013) employed an ROV to retrieve downslope samples, including pumice believed to have been associated with the 2010 eruption. The pumice collected was found to be andesitic in composition. Lava blocks, believed to be from older lava flows, were also sampled. Both the andesitic pumice and lava blocks contained similar weight percentages of SiO2 and MgO, while the pumice had a slightly higher weight percentage of K2O. Embley and others (2013) concluded that due to the abundance of andesite found in samples from the crater and the W flank deposit, both the older and the 2010 eruption of the South Sarigan Seamount were dominantly andesite in composition.

According to Embley and others (2013): “The South Sarigan event is one of the first instances of an explosive, relatively deep, submarine eruption that breached the surface ocean and for which we have quantitative data for the size and extent of the cratering event and deposits to match with seismic and hydroacoustic monitoring information. Submarine craters the size of the one formed during the eruption of South Sarigan are relatively common on seamounts along intra-oceanic arcs... This event, and a deeper and much larger event at Havre Seamount in the Kermadec arc in 2012 . . . underscores how little is known of the eruption history of most submarine arc volcanoes.”

References: Embley, R.W., Y. Tamura, S.G. Merle, T. Sato, O. Ishizuka, W.W. Chadwick Jr., D.A. Wiens, P. Shore, and R.J. Stern. 2014. Eruption of South Sarigan Seamount, Northern Mariana Islands: Insights into hazards from submarine volcanic eruptions. Oceanography 27(2):24–31, http://dx.doi.org/10.5670/oceanog.2014.37.

Green, D. N., Evers, L. G., Fee, D., Matoza, R. S., Snellen, M., Smets, P., & Simons, D., 2013, Hydroacoustic, infrasonic and seismic monitoring of the submarine eruptive activity and sub-aerial plume generation at South Sarigan, May 2010. Journal of Volcanology and Geothermal Research, 257, 31-43.

Searcy, C. 2013. Seismicity associated with the May 2010 eruption of South Sarigan Seamount, northern Mariana Islands. Seismological Research Letters 84(6):1,055–1,061, http://dx.doi.org/10.1785/0220120168

Snellen, M., Evers, L., and Simons, D. G. (2011). “Modeling the long-range acoustic propagation for the May 2010 Sarigan volcano eruption,” in Underwater Acoustics Measurements, edited by J. S. Papadakis (Kluwer, Kos, Greece), pp. 1361–1368

Tamura, Y.; Embley, R. W.; Nichols, A. R.; Ishizuka, O.; Merle, S. G.; Chadwick, B.; Stern, R. J.; Sato, T.; Wiens, D. A.; Shore, P., 2013, ROV Hyper-Dolphin Survey at the May 2010 Eruption Site on South Sarigan Seamount, Mariana Arc, Eos, Transactions of the American Geophysical Union [Paper presented at the 2013 Fall AGU Meeting], San Francisco, California, Abstract V31G-02

Information Contacts: Pacific Marine Environmental Laboratory, Ocean Environment Research Division, EOI Program, Hatfield Marine Science Center, 2115 S.E. OSU Dr., Newport, OR 97365.

Geological Background


South Sarigan seamount, rising to within about 184 meters of the sea surface 12 km south of Sarigan Island, was the site of a short-term explosive submarine eruption in May 2010 that produced a plume of ash and steam to 12 km altitude. Sidescan Sonar imagery taken in 2003 shows an irregular summit with multiple peaks, including a possibly young cone at about 350 m depth, and flank morphology suggests it is a frequently active volcano.

Eruptive History


Summary of Holocene eruption dates and Volcanic Explosivity Indices (VEI).


Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
2010 May 27 2010 May 29 Confirmed 3 Historical Observations

The Global Volcanism Program has no synonyms or subfeatures listed for South Sarigan Seamount.

The Global Volcanism Program has no photographs available for South Sarigan Seamount.

References


The following references have all been used during the compilation of data for this volcano, it is not a comprehensive bibliography. Discussion of another volcano or eruption (sometimes far from the one that is the subject of the manuscript) may produce a citation that is not at all apparent from the title.

Embley R W, Chadwick W W Jr, 2003. MR1 sonar provides new view of sea floor around Mariana Islands. NOAA Ocean Explorer, Submarine Ring of Fire 2003, http://oceanexplorer.noaa.gov/explorations/03fire/logs/feb17/feb17.html.

McGimsey R G, Neal C A, Searcy C K, Camacho J T, Aydlett W B, Embley R W, Trusdell F, Paskievitch J F, Schneider D J, 2010. The May 2010 submarine eruption from South Sarigan seamount, Northern Mariana Islands. Eos, Trans Amer Geophys Union, Fall Meet Suppl, abstr #T11E-07.

Smithsonian Institution-GVN, 1990-. [Monthly event reports]. Bull Global Volc Network, v 15-33.

Volcano Types

Submarine

Tectonic Setting

Subduction zone
Crustal thickness unknown

Rock Types

Major
No Data (checked)

Affiliated Databases

Large Eruptions of South Sarigan Seamount Information about large Quaternary eruptions (VEI >= 4) is cataloged in the Large Magnitude Explosive Volcanic Eruptions (LaMEVE) database of the Volcano Global Risk Identification and Analysis Project (VOGRIPA).
WOVOdat WOVOdat is a database of volcanic unrest; instrumentally and visually recorded changes in seismicity, ground deformation, gas emission, and other parameters from their normal baselines. It is sponsored by the World Organization of Volcano Observatories (WOVO) and presently hosted at the Earth Observatory of Singapore.
EarthChem EarthChem develops and maintains databases, software, and services that support the preservation, discovery, access and analysis of geochemical data, and facilitate their integration with the broad array of other available earth science parameters. EarthChem is operated by a joint team of disciplinary scientists, data scientists, data managers and information technology developers who are part of the NSF-funded data facility Integrated Earth Data Applications (IEDA). IEDA is a collaborative effort of EarthChem and the Marine Geoscience Data System (MGDS).
Smithsonian Collections Search the Smithsonian's NMNH Department of Mineral Sciences collections database. Go to the "Search Rocks and Ores" tab and use the Volcano Name drop-down to find samples.