LESS ENERGETIC ERUPTION

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UWI SRC: Episodic La Soufrière

Eruptions But Less Energetic

Volcanic lightning capturing during the overnight eruption of the La Soufrière Volcano on April 13th, 2021 (Reni King)

Present La Soufrière Alert Level: RED An eruption is in progress or may begin without further warning.

The University of the West Indies Seismic Research Centre (UWI SRC) has advised in their latest scientific advisory at 6:00 PM April 14th, 2021 has said the La Soufrière Volcano’s current pattern of explosions appears to be episodic (stop-and-go) with longer periods between explosions and less energy.

Seismic activity at La Soufrière, St Vincent continued to follow the pattern established yesterday according to the UWI SRC. Bands of tremor about 14 hours apart, separated by swarms of small, long-period (LP) earthquakes.

The latest band of tremors occurred at about 11:35 AM and, as before, was associated with an episode of explosive activity. The explosions produced were gas-rich and did not rise as energetically as previous explosions. No pyroclastic density currents were produced.

The volcano continues to erupt explosively and has now begun to generate pyroclastic density currents. Explosions and accompanying ashfall, of similar or larger magnitude, are likely to continue to occur over the next few days.

In their earlier advisory at 6:00 AM, the UWI SRC advised that small long-period earthquakes continued to gradually increase in number after the explosive activity at 6:30 AM on 13th April. These continued until another episode of explosive activity started at 8:30 PM on 13th April.

This generated continuous seismic tremors, which lasted for four to five hours. After the tremors had died down, small, long-period earthquakes were again recorded, again slowly growing in numbers. The explosions that occurred pulsed for over 40 minutes and produced pyroclastic density currents (PDC’s), which appear to have gone down valleys that drain towards the Rabacca River on the east coast of the island.

PDC’s are hot (200°C-700°C), ground-hugging flows of ash and debris. Lahars (mudflows) were reported in the Sandy Bay Area on 13th April. The volcano continues to erupt explosively and has now begun to generate pyroclastic density currents.

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.

Volcanic Hazard Map for the La Soufrière Volcano, St. Vincent (UWI SRC/NEMO)
Volcanic Hazard Map for the La Soufrière Volcano, St. Vincent (UWI SRC/NEMO)

The alert level remains red. The National Emergency Operations Center continues to be fully functional operating on a twenty-four-hour, around-the-clock basis. NEMO will continue to provide regular updates as they continue to monitor the Volcano.

Official information will originate from St. Vincent and the Grenadines National Emergency Management Organization and the University of the West Indies Seismic

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