St. Vincent & Grenadines + 3 more

St. Vincent & the Grenadines, La Soufrière Volcano, Situation Update #7 (15 April 2021)

Format
Situation Report
Source
Posted
Originally published

Attachments

General Overview

  • La Soufrière volcano Saint Vincent and the Gren- adines (VCT) active since December 29, 2020. Started with effusive eruption activity, formation of a volcanic dome, changes to crater lake and seismic activity.

  • Activity increased since April 8, 2021 3:00 am.
    Prime Minister, VCT gave the order to evacuate the red zone on April 8, 2021 at 4:00 pm and declared the red alert. Explosive eruptions com- menced at 8:42 am on April 9, 2021.

  • On April 11, 2021 at 1:00 am another eruption occurred, followed by a power outage in the NE part of the Island. Power was restored at 6:00 am in Green zone.

  • On April 12, 2021, NEMO reported that at approximately 4:15 am, the dome had collapsed, and pyroclastic flow occurred along the valleys on the eastern and western coasts.

  • Seismic activity at La Soufrière, St Vincent continued in the pattern established on April 12, 2021, with short bands of continuous seismic tremors interspersed with long-period earthquakes.

  • Another explosive event occurred at 6:30 am on April 13, 2021.

  • Seismic activity continued until another episode of explosive activity started at 8:30 pm on April 13, 2021.

  • This generated continuous seismic tremor which lasted for four to five hours.

  • After the tremor had died down, small, long-period earthquakes were again recorded, slowly growing in numbers.

  • The explosions which occurred pulsed for more than 40 minutes and produced pyroclastic density currents (PDCs) which, appear to have gone down valleys that drain towards the Rabacca River on the east coast of the island.

  • PDCs are hot (200°C-700°C), ground-hugging flows of ash and debris.

  • Lahars (mudflows) were reported in the Sandy Bay Area on April 13, 2021.

  • The volcano continues to erupt explosively and has now begun to generate pyroclastic density currents.

  • Its current pattern of explosions appears to be episodic (stop-and-go).

  • Over the past 24 hours the time between each explosion has increased.

  • Explosions and accompanying ashfall, of similar or larger magnitude, are likely to continue to occur over the next few days impacting St. Vincent and neighbouring islands such as Barbados, Grenada,
    Saint Lucia.

  • The volcano is at alert level Red

  • The HEOC is currently finalizing its operational structure through internal discussions. It is anticipated that between 1-2 days, the tangible and human resource needs will be concretized, and support through PAHO and other actors be more formalized.