Table 1 summarizes observations at the crater. Ash is falling on many communities on northern half of the island. . The surface temperatureof this deposit was well in excess of 100C when it was inspected 28 hours after emplacement. New lava dome on the SW edge of the main crater in December 2020. University of the West Indies Seismic Research Centre (UWI-SRC) and National Emergency Management Organisation (NEMO) reported that the lava dome in Soufrire St. Vincents main crater continued to slowly grow during 17-23 March, expanding to the N and S. A team visited the dome on 19 and 23 March to make observations, take measurements, and maintain monitoring equipment. Shepherd J B, 2001. and drifted W. A three-minute period of high-level tremor started at the same time and was flowed by over two hours of lower-level tremor. We determined very early on that nothing serious was happening, since we have seismic stations both on the volcano and throughout the island [figure 3], none of which had recorded any increased seismicity. Explosivity or notable ash venting coincided with the episodes; the spacing between explosive events increased. Gas-and-steam continued to rise from the top of the dome as well as along the contact of the old and new domes. Confirmed Eruption, 0750 BCE 100 years For each MODIS image, the algorithm automatically scans each 1 km pixel within it to check for high-temperature hot-spots. Confirmed Eruption Information gained since our last report gives grounds for optimism with regards to events in the Soufrire and we consider that the probability of a violent eruption is decreasing. The VAAC reported that ash plumes rose to 12.2-16 km altitude throughout the day and continued to drift long distances to the ENE, E, and SE. Information Contacts: H.J. Scientists determined that typical winds diminish the sulfurous odors over much of the island, and the onset of the odors resulted from changes in wind patterns rather than increased gas output or other demonstrable changes. Information Contacts: W. Aspinall, K. Rowley, J. Shepherd, and J. Tomblin, UWI; K. Krafft, Cernay, France; H. Lamb, Univ. The period of tremor lasted until about 2100 and was followed by ongoing small LP and hybrid events. This eruption is particularly noteworthy because of the wide variety of observations made by various scientific teams (from land, low-flying aircraft, a high-altitude research plane, and from satellites). In addition, 40-60 minor seismic events are being reported every 24 hours by high-gain seismographs close to the crater rim. Major mud flows that traveled down the larger valleys (mostly on the W side of the volcano) carved deep, narrow canyons, dramatically exposing pre-1979 valley fill deposits. Credit: NOAA. When the summit was not obscured by clouds, gentle but continuous steam emission was visible. . An explosive eruption began at 0840 on 9 April when an ash plume rose to 8 km (27,900 ft) a.s.l. The highest point on the island is still 226 feet relative to the 3 November datum. "We quickly determined that the reported 'activity' was due to an unusual southerly wind combined with the phenomena of Sahara dust which is common around this time of the year in St. Vincent and which results in very hazy conditions. Max VEI: 3, 1971 Oct 4 6 days - 1972 Mar 20 Consequently, it was impossible to carry out a complete sounding survey. La Soufrire is one of the most active volcanoes in the Lesser Antilles and has a long history of eruptions with the historical records showing eruptions in 1718, 1812, 1814, 1902-1903, 1971-72 and 1979. Watch volcanoes live and catch an eruption in action! A chemical analysis of the rock samples collected from the island on 13 December is now at hand and the following table is an average of three determinations. University of the West Indies Seismic Research Centre (UWI-SRC) and National Emergency Management Organisation (NEMO) reported that seismicity at Soufrire St. Vincent (often simply referred to as La Soufriere) remained low during 17-24 May, with a few long-period and volcano-tectonic earthquakes occasionally recorded. La Palma, El Hierro. Subsequent explosive events were reported at 1115, 1700, and 2050 on the 13th, 0300 and 1200 on 14 April, 1705 on 17 April, 0635 on 22 April, and 2355 on 25 April. A boat trip was made around the island and water temperature recorded at different points in the lake. Two seismic stations were installed on the flank of the volcano at Wallibou (SVV) and at the summit (SSVA) on 6 and 18 January, respectively. A period of high tremor began at 1649 on 18 April. There is one tiltmeter site being set up on the eastern flank of the volcano. Accordingly, the Alert Level remained low at Soufriere St. Vincent. By 17 April an Institut de Physique du Globe de Paris scientist reported that the crater was about 900 m N to S, at least 750 m E to W, and about 100 m deep based on RADAR data. The current eruption is a mild one and involves the growth of a volcanic dome. The zone of destruction from the 1902 eruption (N of the Wallibou and Rabacca Rivers) remains partially evacuated. Much of the northern end of the island was devastated by a major eruption in 1902 that coincided with the catastrophic Mont Pele eruption on Martinique. Nature, 282 (5734), 2428. 4550, p. 1105-1126 (11 papers). Soufrire St. Vincent is monitored by the SRC assisted by the Soufrire Monitoring Unit (SMU) from the Ministry of Agriculture in Kingstown. Seismicity remained low through 11 May with only a few long-period earthquakes recorded by the seismic network. Most of the evidence tends to suggest that there is a slight new lava being extruded at a slower rate into the crater, but whether this decrease in activity is temporary or not is too early to comment on at this stage. This part is the "red zone" of the volcanic hazard maps for St. Vincent and upwards of 16,000 people live in the region. "From the above it is clear that there is no significant difference in silica content between lava flow and pyroclastic material erupted from the Soufrire Volcano. Seismicity dropped to low levels after the explosion on 22 April and remained low through 27 April; only a few VT, LP, and hybrid earthquakes were recorded. Want More? No lava dome was visible, but a possible spine-like protrusion was seen through the clouds. Card 1366 (20 March 1972) Crater observations, 29 February-12 March. St. Vincent and the Grenadines Prime Minister Ralph Gonsalves on Thursday declared a disaster alert prompted by a change in the eruptive activity at the La Soufrire volcano, according to the. respectively. On 11 April 1972, H. Sigurdsson reported that "the Soufriere eruption has now ceased. The SE part of the dome was in line with the pre-existing fumarolic area on the 1979 dome. Both the 1979 and 1902 explosive eruption cycles at La Soufrire were quite significant, ranking. Features are organized into four major categories: Cones, Craters, Domes, and Thermal Features. This was the 30th distinct explosion since the explosive phase began. The true amount of horizontal expansion of the dome is therefore 44 m. The W half of the dome is now 10-20 feet higher than the E half, and the two halves are still separated by a N-S valley. Res., 19: 121-134. Initial findings suggested the presence of hydrogen sulfide in that area and temperatures that had increased around 5-6 degrees; the lead scientist noted that based on their findings there was no increased risk associated with the hot springs. Sulfurous odors are common on the volcano's W flank, but less frequent on other parts of the island. However, monitoring of the volcano by the Seismic Research Unit, University of the West Indies, continues. The Alert Level remained at Orange (the second highest level on a four-color scale). Minor rockfalls continue to take place off the edges of the lava mass, but these are less frequent than in the past weeks as is also indicated by a slight decrease in the number of tremors recorded by the summit seismograph stations. Robertson stated, if the La Soufriere were to have an explosive eruption ash can reach east to Barbados and even further. There is data available for 1 emission periods. Contact Us. Ash venting continued through the night and into 10 April. It seems to rise as a continuous mass and there are no disturbances of any sort except for the minor tremors which we have started to record. Table 6. The October extrusion rate was an order of magnitude less than that of late September and two orders of magnitude less than the May rate. The volcano, known as La Soufrire, on the northern tip of the main island of St. Vincent, in St. Vincent and the Grenadines, had started showing signs of renewed activity in late December. Recorded eruptions date back to 1718, with notable eruptions occurring in 1812, 1902, and 1979. The sticky basaltic andesite lava like the dome that had been forming at La Soufrire (above) can trap gases as new magma rises underneath, creating pressure that can lead to a more explosive style of eruption. Data from four seismometers are telemetered continuously to Trinidad, and scientists visit the volcano every weekend. Juang W S, Bellon H, 1984. At 0400 on 20 April a lahar was detected by the seismic network and lasted for 30 minutes; it possibly traveled down the SE flank. and drifted mainly N over the sea. Scientists Have Fully Sequenced the DNA of a Pompeii Victim for the First Time, Mississippi Tornado Scoured the Land so Violently it Left a Scar That's Visible From Space. Summary of depth and temperature measurements in the Soufriere St. Vincent crater lake, 21 December 1971. Explosive activity of the last 1000 years at La Soufrire, St Vincent, Lesser Antilles. At about 2000 on the 16th, the seismicity changed entirely to rock fracture events, which continued until the explosion of 17 April. Confirmed Eruption It is, however, similar to the second half of the two large historic eruptions of Mt. On 1 March a new seismic station installed at the National Parks Interpretation Center at Bamboo Range on the E side of the volcano became operational. Courtesy of the Seismic Research Unit. Water continues to evaporate from the lake thereby reducing the lake level fractionally; the color of the water is now clearer and more translucent indicating that the sediments disturbed by the initial eruptive activity are resettling. Sulfur dioxide emissions were again measured from the W coast, yielding a flux of 460 tons per day. Visual observations and timing of events and processes on the island have permitted correlation of some of the larger tremors with rockfall and lava creep. Gas plumes continued to damage vegetation in the summit area as well as on the SW flank. (1) 758 518 6106. since 1979, although lava has been erupting at the summit since late December 2020. The composition of the lava is that of a basaltic andesite, virtually identical with older Soufrire lavas such as those at Warbishy River, in the cliffs around the Larikai River, Morne Ronde Point, Campobello Bay, and the numerous lava flows which form the cliffs surrounding the Soufrire crater. This island consists of angular blocks 1-10 m across and appears to be the top of a lava dome standing 200 m above the former lake floor. Activity during December 2020. It is evident from the data of the past three weeks that activity in the Soufriere crater is very slight. Table 1. The resulting ash plumes rose to 10.6-16 km altitude throughout the day. The Alert Level remained at Orange. Rate of lava extrusion in the summit crater of Soufrire St. Vincent, 25 May-25 October 1979, calculated by John Tomblin. Information Contacts: Card 1321 (01 December 1971) Haraldur Sigurdsson, Seismic Research Unit, University of the West Indies. The island is now 145 feet in height above water level, but its growth has decelerated in the last few days. Then, at 8:51 a.m. on April 9, the National Emergency Management announced La Soufrire had erupted. Hot pyroclastic avalanches have accompanied at least three of the explosions. The public was allowed to return to their homes in the Yellow and Orange zones, though access to the Red Zone remained restricted. Depth soundings in the southern part of the Soufriere St. Vincent crater lake, 2 March 1972. The Alert Level was raised to Red at around 1830, and the Prime Minister issued an evacuation order for the Red Zone at the N part of the island, affecting 16,000-20,000 people. There has been no significant change in seismicity since a several-day increase in the number of events in late June and early July. The mean diameter of the lava extrusion increased from 820 m on 4 August to 832 m on 21 August, but the highest point has remained at 130 m above the crater floor since 11 August, after 13 m of vertical growth from 10 July to 11 August. and was associated with a thermal anomaly. Those eruptions lasted months, so if this cycle is similar, people may need to stay away from the volcano (and their homes) for quite a long time. Approximately 7 m of this increase is apparent and not real, i.e., due to the drop in water level between 11-27 February. Information Contacts: J. Tomblin, W. Aspinall, K. Rowley, and J. Shepherd, UWI; A. Kreuger and R. LaPorte, NOAA; M. McCormick, NASA LaRC; F. Mauk, Univ. The public was reminded about lahar hazards during heavy rains. Most of the later explosions were preceded by brief periods (up to 3 hours) of seismic quiet. 10 April 2021. The SO2 plume initially fanned out to the NE, E, and SE across the Atlantic Ocean. Active gas-and-steam emissions originated dominantly at contact areas between the pre-existing 1979 dome and the 2020/21 dome, as well as at the top of the new dome. During the initial stages of the explosion a pyroclastic flow was observed traveling down the W flank, reaching an average speed of 33 km/hour. A team visited the dome on 19 and 23 March to make observations, take measurements, and maintain monitoring equipment. The volcano Alert Level remained at Red. During the period 13-26 May 1972, the situation at the crater continued along the lines stated in the last report. Small VT earthquakes were recorded around 1800. In volcanic eruptions in general the most silica-rich products appear first, when the risk of violent eruptions and explosive activity is greatest. Interactive online tool to view volcano webcams and live seismic recordings side-by-side online. Satellite data showed about 0.4 teragrams (Tg) of SO2 in the plume on 10 April, with some stratospheric injection. The increase in the rate of growth of the island which occurred on 9 February is continuing at present. The NE rim of the 1.6-km wide summit crater is cut by a crater formed in 1812. The condition was first noted by a pilot who flew over Soufrire on 31 October. The average SO2 flux was 992 tons/day on 23 April, again recorded from the W coast. On 15 September the Alert Level was lowered to Yellow and remaining evacuees were allowed to return home. To convert, we can use a factor of 2. Robertson R E A, 1995. By the end of May, the new dome had grown to ~500 m in diameter and 60 m in height. . When the lake was at its highest level on November 20th, it was thus some 92.5 feet above the normal pre-eruption level. Additional satellite data. The N part of this valley is the most actively steaming area of the dome. Almorales, Seismic Research Unit, University of the West Indies. The Soufrire has now been in eruption for over four months and has comfortably exceeded this initial period of high uncertainty. Overnight during 10-11 April ash again fell island-wide, and also in the Grenadines (to the SSW), Barbados, and Saint Lucia (50 km NNE). Click on the index link or scroll down to read the reports. Lahars in the Red and Orange zones were recorded by the seismic network at 0900 and 1000 on 27 April, during and after rainfall. La Soufrire, a stratovolcano on the Caribbean island of Saint Vincent in Saint Vincent and the Grenadines, began an effusive eruption on 27 December 2020. In each of these eruptions there was an initial, highly explosive phase which lasted several months, and this was followed by a second phase in which fresh lava welled up quietly into the crater to build a dome. Magmagenesis at Soufriere volcano, St Vincent, Lesser Antilles Arc. SRC collected rock samples from the new lava dome and sent them to scientists from the University of East Anglia, University of Plymouth, and University of Oxford on 16 January 2021 as a collaborative project to analyze their composition and compare them with the composition of rocks erupted in 1902, 1971, and 1979. Dozens of individuals have been . Thus the present eruption in St. Vincent is likely to continue for one year and could possibly continue for two. La Soufriere, located near the northern tip of the main island of St Vincent, last erupted in 1979, and a previous eruption in 1902 killed some 1,600 people. University of the West Indies Seismic Research Centre (UWI-SRC) and National Emergency Management Organisation (NEMO) reported that the lava dome in Soufrire St. Vincents main crater was an estimated 428 m long, 217 m wide, 80 m high, and had a volume of 4.45 million cubic meters by 27 January. According to a news article, residents of the island of St.Vincent reported smelling sulfur in towns as far S as Kingstown. Soufrire St. Vincent is the northernmost stratovolcano on St. Vincent Island in the southern part of the Lesser Antilles. Latest nearby quakes. Updated measurements were taken of the new crater, by 17 April according to an Institut de Physique du Globe de Paris scientist. The most noticeable feature of this period has been the very small number of crater tremors, and no tremors have been recorded since 7 March. Thermal satellite data. 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. The rate of rise of the rocks has decreased slightly to about one foot per day but the rate at which the water level is dropping is still about nine inches per day. For the first time sulfur dioxide emissions were successfully measured by ground-based instruments; scientists recorded 809 tons per day from a Coast Guard boat along the W coast. A report on 6 February stated that the dome continued to spread laterally N and S, with N as the dominant growth direction. NEMO reported that 12,775 people were displaced by 19 April, with 6,208 people in 85 public shelters and 6,567 people (1,800 families) in private shelters. Max VEI: 0, 1718 Mar 26 (?) Confirmed Eruption. SYNOP codes from weather stations and buoys. Aseismic lava extrusion persists; heavy rains generate large secondary mudflows. Expand each entry for additional details. Two thermal hotspots were detected using the MODVOLC thermal algorithm on 24 April. The Dust Veil Index for the 1902 eruption of Soufrire was calculated at 300; the Krakatau 1883 eruption = 1,000. Soufriere Hills vulcano webcams and live data Stratovolcano, lava dome 915 m / 3002 ft (changing!) - Part I.. Why Is a Huge Seaweed Blob Headed for Florida? Scientists visited the dome on 16 January and collected rock samples from the W part of the dome. Seismicity dropped to low levels after the explosive event and remained at low levels through 27 April; only a few LP, hybrid and VT earthquakes were recorded. Around 2100 the seismic network recorded multiple lahars, though their location could not be determined. The following report on the subject comes from SRU's Richard Robertson. and drifted mainly ENE. The Alert Level remained at Orange (the second highest level on a four-color scale). Courtesy of the Seismic Research Unit. 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