The GNSS station at St. John’s, Saba. (KNMI photo)
SABA--The Royal Netherlands Meteorological Services KNMI has developed a webpage dedicated to the volcanoes of Saba and St. Eustatius. The webpage
www.knmidc.org/volcanoes contains information about the monitoring and setting of the Mt. Scenery and The Quill volcanoes. Visitors to the site can view the monitoring data and are encouraged to make suggestions for improvements.
KNMI has worked in the Caribbean Netherlands since 2006. The islands became public entities of the Netherlands in 2010. KNMI monitors the two volcanoes, the regional seismicity and provides weather information.
KNMI is working on a system to automatically locate earthquakes in the Caribbean region, similar to the automatic earthquake system in Groningen, the Netherlands, an area that regularly experiences earthquakes, mostly due to the extraction of natural gas.
Residents of Statia and Saba are asked to assist KNMI with information when they have felt an earthquake or tremor. The form can be found on the KNMI website
Through the continuous support of Saba’s telephone company SATEL, the three seismometers placed throughout the island are functioning well and produce data of good quality for the purpose of detecting earthquakes. For example, the seismometers measured ground velocities up to 0.5 millimetres per second (mm/s) during the magnitude 6 earthquake northwest of Puerto Rico on September 24.
The two Global Navigation Satellite System (GNSS) stations at St. John’s and at the airport, operational since January 2018 and February 2019, respectively, have been functioning well.
The data show a very small movement of the GNSS stations towards the northeast. This movement is due to plate tectonic movements whereby the North and South American plates subduct underneath the Caribbean plate.
KNMI has been looking for a good location for a third GNSS, combined with a seismometer and is asking residents to help with finding a suitable location. The location needs to meet a number of conditions: it should be in the northwest section of the island; have a sky view; have solid, preferably rock ground; be accessible within 45 minutes on foot; be at a minimum of 150 metres from the sea; and be at a minimum 150 metres from a vertical cliff.
KNMI was able to collect temperature data from the hot spring opposite Green Island in February 2019. Both temperature probes recorded data for three months. However, one probe started to fail after the first month. The maximum temperature of the hot spring is around 82 degrees Celsius, but it fluctuates due to the heavy mixing with seawater which in turn is influenced by the changing of the tides.
A KNMI team will be visiting Saba again in January 2020.