La Soufrière Domes Destroyed, New Crater Forms

SAR imagery, able to penetrate through miles of volcanic ash and clouds, captured a 3D image of what is now the La Soufrière Volcano summit. (Capella Space)

Present La Soufrière Alert Level:ORANGEThere is a highly elevated level of seismic and/or fumarolic activity or other unusual activity. An eruption may begin with less than twenty-four hours’ notice.

The 1979 and 2020-2021 lava domes of the La Soufrière Volcano have been destroyed by explosive eruptions. This is according to UWI Professor and UWI SRC Geologist Richard Robertson.

From satellite imagery, namely SAR technology, Robertson said, “We now know that the new dome and old dome are gone,” in an interview on NBC St. Vincent and the Grenadines Radio on April 12th, 2021. Synthetic-aperture radar (SAR) is a form of radar used to create two-dimensional images or three-dimensional reconstructions of objects. SAR uses the radar antenna’s motion over a target region to provide finer spatial resolution than conventional beam-scanning radars.

He also added that “we now have a crater at the summit of La Soufrière, a new vent that is estimated to be 825 meters and 715 meters in dimensions.” Robertson explained that this huge crater or hole in the mountain is where “the action is happening,” referring to La Soufrière’s repeated explosive eruptions. The crater is near the center of the mountain where both the 1979 and 2020-2021 domes were located.

1st April, 2021. Panoramic view of the new dome take from the Windward trail. Photo credit: UWI-SRC, Prof Robertson.
1st April, 2021. Panoramic view of the new dome taken from the Windward trail. (UWI-SRC, Prof Robertson)

Roberson also explained that the volcanic ash falling over St. Vincent, Barbados and other areas were comprised of the old lava domes.

This new crater in the mountain is freely producing explosions and Robertson said “it probably doesn’t have anything in it other than fresh magma.”

As the eruption unfolds and gradually slows down, Robertson said La Soufrière could produce a new lava dome to end off the activity, like it did in 1979 or it could end up with an open crater.

The professor also explained, “When La Soufrière is erupting in the future, it is going to be a very different mountain. You’re going to see things much differently. There is no more dome.”

The La Soufrière Volcano went into a state of unrest in December 2020, with an effusive eruption beginning on December 27th, 2020. The volcano then went into an explosive state on April 9th, 2021 and the alert level remains at red. Evacuation orders remain in effect for Orange and Red Hazard Zones in St. Vincent.

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)

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

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