Contents of Monthly Reports

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

All times are local (= UTC - 2 hours)

02/2003 (BGVN 28:02) Lava lake detected in satellite imagery during 1995-2002

Although previous eruptions have been recorded in the South Sandwich Islands (Coombs and Landis, 1966), ongoing volcanic activity has only recently been detected and studied. These islands (figure 1) are all volcanic in origin, but sufficiently distant from population centers and shipping lanes that eruptions, if and when they do occur, currently go unnoticed. Visual observations of the islands probably do not occur on more than a few days each year (LeMasurier and Thomson, 1990). Satellite data have recently provided observations of volcanic activity in the group, and offer the only practical means to regularly characterize activity in these islands.

Figure 1. The South Sandwich Island archipelago, located in the Scotia Sea. The South Sandwich Trench lies approximately 100 km E, paralleling the trend of the islands, where the South American Plate subducts westward beneath the Scotia Plate. Courtesy Hawaii Institute of Geophysics and Planetology and British Antarctic Survey.

Using Advanced Very High Resolution Radiometer (AVHRR) data, Lachlan-Cope and others (2001) discovered and analyzed an active lava lake on the summit of Saunders Island (figure 2) that was continuously present for intervals of several months between March 1995 and February 1998; plumes originating from the island were observed on 77 images during April 1995-February 1998. J.L. Smellie noted that during helicopter overflights on 23 January 1997 (Lachlan-Cope and others, 2001) "dense and abundant white steam was emitted from the crater in large conspicuous puffs at intervals of a few seconds alternating with episodes of less voluminous, more transparent vapour." Smellie also observed that the plume commonly extended ~8-10 km downwind.

Figure 2. Map of Saunders Island, adapted from Holdgate and Baker (1979). Lighter shaded stippled areas show rock outcrop, the remainder is snow or ice covered. Relief is shown by form lines that should not be interpreted as fixed-interval contours. Courtesy Hawaii Institute of Geophysics and Planetology and British Antarctic Survey.

The MODIS Thermal Alert system also detected repeated thermal anomalies throughout 2000-2002 in the summit area (figure 3), indicating that activity at the lava lake has continued. Anomalous pixels (1 km pixel size) were detected intermittently and were all 1-2 pixels in size, consistent with the relatively small confines of the crater. The timing of anomalous images in this study likely has more to do with the viewing limitations imposed by weather (persistent cloud cover masks any emitted surface radiance in the majority of images) than it has to do with fluctuations in activity levels, so this plot of radiance (figure 4) should not be used as a proxy for lava lake vigor.

Figure 3. Selected MODIS images showing thermal anomalies on Saunders Island. Band 20 (3.7 µm) is shown here. Anomalous pixels on Saunders Island correspond to the lava lake in the summit crater of Mt. Michael volcano. Images are not georeferenced for purposes of radiance integrity, therefore coastlines are approximate. Courtesy Hawaii Institute of Geophysics and Planetology and British Antarctic Survey.

Figure 4. Summed radiance of anomalous pixels in each image. Band 21 (3.9 µm) was used for these plots. Points show the result for each image, and the line is a three point running mean of values. Courtesy Hawaii Institute of Geophysics and Planetology and British Antarctic Survey.

References. Coombs, D.S., and Landis, C.A., 1966, Pumice from the South Sandwich eruption of March 1962 reaches New Zealand: Nature, v. 209, p. 289-290.

Holdgate, M.W., and Baker, P.E., 1979, The South Sandwich Islands, I, General description: British Antarctic Survey Science Report, v. 91, 76 p.

Lachlan-Cope, T., Smellie, J.L., and Ladkin, R., 2001, Discovery of a recurrent lava lake on Saunders Island (South Sandwich Islands) using AVHRR imagery: Journal of Volcanology and Geothermal Research, v. 112, p. 105-116.

LeMasurier, W.E., and Thomson, J.W. (eds), 1990, Volcanoes of the Antarctic Plate and Southern Oceans: American Geophysical Union, Washington, D.C., AGU Monograph, Antarctic Research Series, v. 48.

Wright, R., Flynn, L.P., Garbeil, H., Harris, A.J.L., and Pilger, E, 2002, Automated volcanic eruption detection using MODIS: Remote Sensing of Environment, v. 82, p. 135-155.

Information Contacts: Matt Patrick, Luke Flynn, Harold Garbeil, Andy Harris, Eric Pilger, Glyn Williams-Jones, and Rob Wright, HIGP Thermal Alerts Team, Hawai'i Institute of Geophysics and Planetology (HIGP) / School of Ocean and Earth Science and Technology (SOEST), University of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (http://hotspot.higp.hawaii.edu/, Email: patrick@higp.hawaii.edu); John Smellie, British Antarctic Survey, Natural Environment Research Council, High Cross, Madingly Road, Cambridge CB3 0ET, United Kingdom (URL: http://www.antarctica.ac.uk/, Email: jlsm@pcmail.nerc-bas.ac.uk).

03/2004 (BGVN 29:03) A MODIS thermal alert on 7 May 2003 (no secondary confirmation)

The only previous report on the remote Michael volcano was in BGVN 28:02, which commented on a lava lake detected by satellite imagery over the period 1995-2002. A review of MODIS data for the period from that report (end 2002) to 16 March 2004 (UTC) reveals one thermal alert, on 7 May 2003 (UTC). No corroborative report is available, although previous alerts were interpreted as possibly representing lava lake activity.

Information Contact: Rob Wright, Luke Flynn, and Eric Pilger; MODIS Thermal Alert System, Hawaii Institute of Geophysics and Planetology (HIGP), School of Ocean and Earth Science and Technology, University of Hawaii at Manoa (URL: http://modis.higp.hawaii.edu/, Email: wright@higp.hawaii.edu, flynn@higp.hawaii.edu, and pilger@higp.hawaii.edu).

04/2006 (BGVN 31:04) Lack of new thermal signals suggesting any eruption since October 2005

The last reported activity of Mount Michael was noted in the SI/USGS Weekly Report of 12-18 October 2005. At that time the first MODVOLC alerts for the volcano since May 2003 indicated an increased level of activity in the island's summit crater and a presumed semi-permanent lava lake that appeared confined to the summit crater. Those alerts occurred on 3, 5, and 6 October 2005. Since that time there has been no additional information concerning Mount Michael and presumably little to no activity.

Information Contacts: Matt Patrick, Luke Flynn, Harold Garbeil, Andy Harris, Eric Pilger, Glyn Williams-Jones, and Rob Wright, HIGP Thermal Alerts Team, Hawai'i Institute of Geophysics and Planetology (HIGP) / School of Ocean and Earth Science and Technology (SOEST), University of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (http://hotspot.higp.hawaii.edu/, Email: patrick@higp.hawaii.edu); John Smellie, British Antarctic Survey, Natural Environment Research Council, High Cross, Madingly Road, Cambridge CB3 0ET, United Kingdom (URL: http://www.antarctica.ac.uk/, Email: jlsm@pcmail.nerc-bas.ac.uk).

10/2006 (BGVN 31:10) Clear IR satellite view on 28 October 2006 suggests lava inside the crater

Matt Patrick sent a new Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) image, collected 28 October 2006 over Saunders Island . In his opinion this is the best image collected to date owing to the lack of a plume obscuring the summit crater, which was a problem in all previous images. The improved image provides a clear view of the crater (figures 5 and 6).

Figure 5. An ASTER image of Mt. Michael created using energy in the visible near-infrared wavelength ("VNIR"; bands 3-2-1, RGB), with the inset showing a closer view of the summit crater. There are two small near-IR anomalies (band 3, 0.807 microns wavelength) in the otherwise dark center of the crater, shown as red spots in the colored image. The two anomalies suggest very high temperatures and support the idea that fresh lava may reside at the surface or a shallow level in the crater. Courtesy of Matt Patrick.

Figure 6. The ASTER Short Wave Infrared (SWIR; band 9, 2.4 microns) image with a conspicuous anomaly at the summit, with numerous saturated pixels. Courtesy of Matt Patrick.

Analyzing the VNIR, SWIR, and Thermal Infrared (TIR) (not shown in figures 5 or 6) images together shows that the outer crater is 500-600 m wide, with a 180m high-temperature crater interior. The latter shows up as an SWIR anomaly and may indicate the rough extent of active lava flow being ~ 180 m wide. Matt Patrick chose Villarrica volcano in Chile for comparison to Mt. Michael (figure 7) since it presents a potentially good analogue in terms of morphology and activity style. Maximum radiant heat flux values were similar (up to ~ 150 MW), suggesting that the maximum intensity of activity may be similar. Mt. Michael shows a much lower frequency of thermal alerts, which may be the result of more frequent cloud cover in the South Sandwich Islands or a greater depth to molten lava in the Mt. Michael crater.

Figure 7. The real-time satellite thermal monitoring (MODVOLC) radiant heat flux values for Michael and Villarrica volcanoes during the period 2000-11 November 2006. Courtesy of Matt Patrick.

Table 1 shows a summary of thermal anomalies and possible eruptions from Moderate Resolution Imagine Spectroradiometer (MODIS) satellites since November 2005. The last reported activity of Mount Michael was noted in the SI/USGS (Smithsonian Institution/U.S. Geological Survey) Weekly Volcanic Activity Report of 12-18 October 2005 (see BGVN 31:04). At that time the first MODVOLC alerts for the volcano since May 2003 indicated an increased level of activity in the island's summit crater and a presumed semi-permanent lava lake that appeared confined to the summit crater. Those alerts occurred on 3, 5, and 6 October 2005.

Table 1. Thermal anomalies measured by MODIS satellites for Mount Michael for the period 3 October 2005 to 1 November 2006. All of the anomalies appeared on the SW side of the volcano. Courtesy of Hawai'i Institute of Geophysics and Planetology (HIGP) Thermal Alerts Team.

    Date           Time (UTC)    Number of pixels    Satellite

    01 Nov 2006      0125               1              Terra
    31 Oct 2006      1600               1              Aqua
    21 Oct 2006      1120               1              Terra
    20 Oct 2006      0250               2              Aqua
    20 Oct 2006      0100               3              Terra
    21 Jul 2006      0120               1              Terra
    09 Jun 2006      0920               2              Aqua
    21 Jan 2006      0100               1              Terra
    20 Dec 2005      0100               1              Terra
    06 Oct 2005      0115               1              Terra
    05 Oct 2005      0220               1              Aqua
    03 Oct 2005      0045               1              Terra

References. Lachlan-Cope, T., Smellie, J.L., and Ladkin, R., 2001, Discovery of a recurrent lava lake on Saunders island (South Sandwich Islands) using AVHRR imagery: Journal of Volcanology and Geothermal Research, vol. 112, no. 1-4, p. 105-116 (authors are members of the British Antarctic Survey).

LeMasurier, W.E., and Thomson, J.W. (eds), 1990, Volcanoes of the Antarctic Plate and Southern Oceans: American Geophysical Union, Washington, D.C., AGU Monograph, Antarctic Research Series, v. 48.

Information Contacts: Matt Patrick, Michigan Technological University, Houghton, MI (Email: mpatrick@mtu.edu); Thermal Alerts Team, Hawai'i Institute of Geophysics and Planetology (HIGP), School of Ocean and Earth Science and Technology (SOEST), University of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://hotspot.higp.hawaii.edu/ ); John Smellie, British Antarctic Survey, Natural Environment Research Council, High Cross, Madingly Road, Cambridge CB3 0ET, United Kingdom (URL: http://www.antarctica.ac.uk/, Email: jlsm@pcmail.nerc-bas.ac.uk); ASTER Science Project Teams, United States and Japan (URL: http://asterweb.jpl.nasa.gov/team.asp and http://www.science.aster.ersdac.or.jp/en/science_info/).

04/2008 (BGVN 33:04) No thermal anomalies detected since December 2006

The frigid, remote, and uninhabited region of Michael volcano is seldom visited. Thermal anomalies detected by satellite-based MODIS instruments, processed using the MODVOLC algorithm by the Thermal Alerts System of the Hawai'i Institute of Geophysics and Planetology, provide some data about possible eruptive activity (BGVN 28:02, 29:03, 31:04, and 31:10). During 3-6 October 2005 there were three days with thermal anomalies (BGVN 31:04). MODIS data indicates that anomalous pixels were also detected on 19 December 2005 (20 December UTC) and on 20 January 2006 (21 January UTC) (BGVN 31:10). The most recently reported MODIS thermal anomalies indicated activity during 19-21 October 2006 (20-21 October UTC) and again on 31 October-1 November 2006 (BGVN 31:10). The source of these anomalies was an inferred lava lake in a central vent as shown on an Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) image collected 28 October 2006 (BGVN 31:10). Additional anomalies occurred on 13 November and 6 December 2006 (7 December UTC). No anomalies were measured after that date through May 2008. Since August 2000 there have been six periods when thermal anomalies were detected in satellite imagery (table 2).

Table 2. Eruptive periods at Michael as inferred from MODIS thermal data from January 2000 through May 2008. Courtesy of the Hawai'i Institute of Geophysics and Planetology Thermal Alerts System.

    Date (UTC)                 Thermal pixel data      Bulletin reference

    30 Aug 2000-03 Feb 2001     3 days with pixels     BGVN 28:02
    05 Aug 2001-21 Nov 2001    10 days with pixels     BGVN 28:02
    05 Jul 2002-01 Nov 2002    12 days with pixels     BGVN 28:02
    07 May 2003                 2 anomalous pixels     BGVN 29:03
    03 Oct 2005-21 Jan 2006     5 days with pixels,    BGVN 31:04, 31: 10
                                three during 3-6 Oct
    09 Jun 2006-07 Dec 2006     9 days with pixels     BGVN 31:10, 33:04

Information Contacts: Hawai'i Institute of Geophysics and Planetology (HIGP) Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://hotspot.higp.hawaii.edu/).

02/2013 (BGVN 38:02) Eruption from ‘new’ vent

Matthew Patrick (USGS-HVO) notified Bulletin editors that in late 2012 images from thermal sensing satellites showed a ‘new’ active vent on Mount Michael on Saunders Island in the South Sandwich Islands (see location map, figure 1 in BGVN 28:02). This prompted scrutiny of the same vent in earlier images. Patrick noted that, although the vent was first identified in the 2012 images, it also appeared as activity in satellite images starting in 2006. The South Sandwich Islands are generally devoid of vegetation and habitants, and are largely ice-bound. Thus, satellite thermal alerts are strong evidence of volcanism.

Patrick shared with us the following information from a paper by Patrick and Smellie (in review) about the vent, labeled as Old Crater (SE and outside of main crater, see figure 2 in BGVN 28:02). ASTER [Advance Spaceborne Thermal Emission and Reflection Radiometer] imagery provided “new information on the small subordinate crater, marked as ‘Old Crater’ by Holdgate and Baker (1979), presumably because it was inactive at the time of their observations.” An ASTER image on 28 October 2006 showed an apparent SWIR [short-wave infrared] anomaly at Old Crater. The crater itself appeared to be snow-free and was approximately 150 m in diameter. An ASTER image from 5 January 2008, showed a steam plume coming from this vent, which appeared to be about 190 m wide, as well as a TIR [thermal infrared] anomaly. A very high resolution image from November 2009 available on Google Earth showed a small steam plume emanating from the crater, which is about 190 m wide (figure 8). An ASTER image from 17 November 2010, showed apparently recent eruptive activity in Old Crater, evidenced by tephra fallout emanating from the crater and a small TIR anomaly (at the time there was also a TIR anomaly in the main crater). According to Patrick and Smellie, the plume, tephra fall, SWIR anomalies, and crater enlargement (from 150 to 190 m) indicated that this vent had reactivated by late 2006.

Figure 8. Annotated Google Earth imagery of Michael volcano (Saunders Island) acquired on 19 November 2009. (a) Saunders Island is mostly glacier covered, and steam plumes rose from the summit area. The scale bar indicates a distance of ~2.4 km. (b) A close up of the summit area that clearly shows steam plumes emanating from both the summit crater as well as the snow-filled ‘Old Crater’ (as termed by Holdgate and Baker, 1979). The scale bar indicates a distance of ~0.5 km. Courtesy of Google Earth.

MODVOLC satellite thermal alerts measured from the volcano since our last Bulletin report (BGVN 33:04, activity through May 2008) and to 4 April 2013 are shown in Table 3. A solitary alert appeared 25 October 2008, followed by a four year period of apparent inactivity. Then, another solitary alert was measured in late June 2012, followed by alerts for two days in October 2012 and two days in November 2012. Patrick noted that occasional and sporadic alerts are very typical for Michael.

Table 3. Satellite thermal alerts measured by MODVOLC over Michael from 2008-February 2013. Pixel sizes generally range from 1-1.5 km². Note that previous satellite thermal alerts for Michael were listed in BGVN 31:10 (October 2005-November 2006) and 33:04 (August 2000-May 2008). Courtesy of MODVOLC.

Date           Time    Pixels    MODIS
               (UTC)             Satellite

25 Oct 2008    0100      1       Terra
30 Jun 2012    0100      1       Terra
2 Oct 2012     0110      1       Terra
28 Oct 2012    0200      2       Aqua
28 Oct 2012    1125      2       Terra
14 Nov 2012    0055      3       Terra
22 Nov 2012    1120      2       Terra

References. Patrick, M.R., and Smellie, J.L., (in review), A spaceborne inventory of volcanic activity in Antarctica and southern oceans, 2000-2010, Antarctic Science, in review in 2013.

Holdgate, M.W., and Baker, P.E., 1979. The South Sandwich Islands: I. General description, British Antarctic Survey Scientific Reports, No. 91, pp. 1-76.

Information Contacts: Matthew Patrick, Hawaiian Volcano Observatory (HVO), U.S. Geological Survey, PO Box 51, Hawai'i National Park, HI 96718, USA (URL: http://hvo.wr.usgs.gov/, Email: mpatrick@usgs.gov); MODVOLC, Hawai'i Institute of Geophysics and Planetology (HIGP) Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://hotspot.higp.hawaii.edu/).