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La Soufriere: Slight uptick in seismic activity over the weekend


ead scientist Llyod Lynch who is monitoring the La Soufriere volcano in St Vincent and the Grenadines said there was a slight uptick in activity over the weekend but the situation seems to be settling back down.

Speaking on NBC Radio on Monday, Lynch said the activity was probably attributed to high levels of precipitation.

He said in prior reports the team would have recorded 10 small earthquakes (sometimes less) per day however during the precipitation it jumped to about 40 on two consecutive days.

Lynch speaking on Monday said 25 were recorded over the past 24 hours.

“It seems like things have bumped up and with less precipitation, it is settling back down.”

Gas measurements (SO2 flux) taken last Friday returned a reading of 472 tonnes per day which he said is within the ballpark of what they have been reporting. No lahars were reported.

Lynch explained that the uptick in activity does not mean much in terms of threats to the population. He said with the increase in the level of precipitation and the small rise in the water table, there is more interaction with volcanic system’s hydrothermal regions.

He said because of this, small shallow earthquakes will be recorded.

Meanwhile, the UWI Seismic Research Centre in its update today says seismic activity at La Soufrière has remained low since the tremor associated with the explosion and ash venting on April 22.

It says in the last 24 hours, only a few small earthquakes have been recorded.

Persistent steam emissions from a few regions inside the crater continue to be the dominant observable feature.

Thermal anomalies in the crater continue to be detected but do not indicate an explosive event is imminent but that there is a source of heat, most likely from a small body of magma left over, close to the floor of the Summit Crater.

Measurement of the sulphur dioxide (SO2) flux was carried out off the west coast on June 18 and yielded an average SO2 flux of 479 tonnes per day.

SO2 can be an indicator that fresh magma from a deeper source is being degassed.

It adds that an increase in the smell of sulphur in Richmond and Chateaubelair regions has also been reported. This can happen when wind direction carries the SO2 plume towards this direction.

Work is underway to restore capacity lost during the explosive phase of the eruption. This will continue until the end of June 7.

The volcano continues to be in a state of unrest.

While volcanic activity has been on a decline the continued presence of near-surface hot spots, daily seismic activity and substantial degassing is proof that the system is still in unrest and escalation in activity can still take place with little or no warning.

The volcano is at alert level orange.

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