Volcanic & seismic activity monitored on Saba
SABA–The Royal Netherlands Meteorological Institute (KNMI) continues its volcanic/seismic monitoring work on Saba despite the challenges of the COVID-19 pandemic with associated travel restrictions and delayed delivery of new equipment.
KNMI experts will return to the island in April 2021 to collect data and to inspect, and repair, monitoring equipment in Saba. There are also plans to install a new Global Navigation Satellite System (GNSS)/seismic monitoring station on the North Coast of the Island.
In its most recent update, KNMI volcanologist Elske De Zeeuw-van Dalfsen and seismologist Reinoud Sleeman explained that seismometers “SABY” at the airport, “SABW” in Windward side and “SABA” at St. John’s are functioning well and produce data of good quality for the purpose of detecting earthquakes. The fourth seismometer “SABQ” in The Bottom is currently not functioning due to technical issues, and is awaiting repair by the manufacturer.
The two GNSS stations in St. John’s and at the airport, worked well during most of 2020. The GNSS station in St. John’s has been operational since January 2018 and the other at the airport since February 2019. In January 2020, the KNMI installed a GPS (Global Positioning System) receiver in The Bottom. This instrument measures its precise location on the ground, allowing to track its movement.
The new GNSS/seismic station at Grey Hill, along the North Coast, is planned for April 2021. The equipment and construction materials will be shipped to Saba in February. This installation, unlike the other GNSS/seismic equipment, will be completely stand-alone. Satellite communication will be used to send data to the KNMI and solar panels/batteries will be used to power this site in this uninhabited area.
In January 2020, during the last visit of the KNMI experts, the continuous temperature data from the underwater hot spring opposite Green Island were collected. Measurements at the hot spring are taken every 20 minutes and stored locally.
The maximum temperature remains constant at 82 degrees Celsius. During the next visit in April, the experts will collect the 2020 temperature data at the hot spring. In March 2020, a member of the public reported multiple cracks in the area of the Green Gut along the road between English Quarter and Hell’s Gate. The crack along the wall was 60 cm deep and had warm moist air venting from it at about 50 °C. The KNMI experts will bring a thermal camera to closely inspect the area upon their next visit.
Rangers of the Saba Conservation Foundation (SCF) in March 2020 reported dead mountain mahogany trees in an area close to the top of Mt. Scenery. A SCF team under the guidance of the KNMI investigated the area for other signs of volcanic activity such as volcanic deposits (ash, sulphur), or fumes but no such evidence was found, suggesting that volcanic activity did not cause the trees to die. In the update, the KNMI also addressed the increased levels of activity of several volcanoes in the Caribbean. It was explained that the Caribbean volcanoes were all formed by the same process, namely the subduction at the plate boundary. However, the volcanoes do not share the same magma chamber, nor are they connected by long magma conduits. A volcanic eruption on one island can therefore not trigger an eruption on another island, the KNMI assured.
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