Seismologist: Volcanic tsunami won't be a threat to region

IF THERE is a tsunami as a result of the La Soufriere eruption, it will not be as energetic as one generated by a tectonic plate shift, says seismologist Dr Joan Latchman.

La Soufriere first erupted last Friday, after over four decades of dormancy, and did so three times that day. Since then, there have been several further eruptions causing long-period earthquakes, almost continuous ash venting, and pyroclastic flow.

National Geographic described pyroclastic flow as a dense, fast-moving flow of solidified lava pieces, volcanic ash, and hot gases.

“This volcano is located such that its pyroclastic flow can enter the sea. Tsunamis can be associated with volcanic eruptions that generate pyroclastic flow entering the sea but these are usually low-level tsunamis.

"They are highly localised to the islands where the volcano is located and very nearby islands. They are not usually tsunamis that would affect the region.”

Latchman said that as of Thursday morning, the last explosion was on Wednesday at 11.35 am. Gases did not rise as energetically as previous explosions and there was no pyroclastic flow.

There were bands of tremor 13 to 15 hours apart separated by small long-period earthquakes. And, around 2.30 am on Thursday there was increased venting but there no explosion.

Latchman, who is on a short-term contract with the UWI Seismic Research Centre (UWI-SRC), will be succeeded by seismologist Dr Rodrigo Conteras Arratia from Chile. He has already joined the UWI-SRC team and will be assisting in the scientific research on La Soufriere.

She said she is in the process of handing over the reins to Arratia, who is a highly qualified seismologist, although she intends to continue to be associated with the SRC. She believes he is going to be a “wonderful asset” to the agency.

“For him to be able to hit the ground running he would need to come up to speed with what we have done here, and how we do it here, to be able to tailor it to how he would prefer to do it going forward. Because, as a much younger person, certainly he would have things he would want to introduce and do in a different way, making use of technologies that are available to him.”

In addition to a new seismologist, the SRC may soon get new equipment. According to a press release on Thursday, UWI-SRC received US$17,150 grant from the Caribbean Catastrophe Risk Insurance Facility to support its efforts in monitoring the ongoing eruption of La Soufriere.

It said the grant would be used to fund equipment, rebuild existing monitoring sites and provide back-up equipment.

“As a result of this investment, new communication and ground deformation equipment will now be added to those already deployed, increasing the UWI-SRC’s capacity to understand the volcano’s eruptive processes and provide advanced warning of hazardous activity to the Vincentian population in the future.”