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La Soufriere SCIENTIFIC UPDATE
1. Seismic activity has remained low with only a few long-period, hybrid and volcano-tectonic earthquakes have been recorded and there was no further tremor.
2. Signals from several lahars (mudflows) were recorded between 9 and 10 am today, during and after a period of rainfall.
3. A lahar is a rapidly flowing dense mixture of rock debris, ash and water. They have the consistency of wet concrete as they flow and can happen during and after eruptions.
4. Following the rainfall, large amounts of steam could be seen billowing up from a valley south of the summit.
5. This would have been generated when the runoff encountered buried volcanic deposits that were still hot.
6. The volcano continues to erupt. Explosions with accompanying ashfall, of similar or larger magnitude, can restart with little or no warning.
7. The volcano is at alert level Red.
8. Visit https://volcanoes.usgs.gov/volcanic_ash/resources.html for Global Ash Impact posters and material from the International Volcanic Hazard Health Network on volcanic ash and hazard guides.
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Photo analysis: multiple areas of venting and a possible lava spine*. It was noted that tephra** has filled the crater so that it now reaches the top of southwestern part of the summit. This can make it easier for pyroclastic density currents PDCs to get out of the summit crater.
*spine – a volcanic feature of solid lava squeezed out from a vent that grows upwards forming a tall feature. It can range from tens to hundred of meters inn height and width once it remains stable.
**Tephra – materials of all types and sizes that are erupted from a volcano and deposited from the air onto surrounding areas.
Photo credit: Roderick Stewart, MVO/UWI-SRC.
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API – The Agency For Public Information : St. Vincent and the Grenadines
CDEMA – Caribbean Disaster Emergency Management Agency
NEMO St. Vincent and the Grenadines
Sir Godfrey Gregg
