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The Saba Island Council on Thursday, January 23 met with representatives of the Royal Netherlands Meteorological Institute (KNMI) Elske de Zeeuw-Van Dalfsen and Reinoud Sleeman.
Discussed with volcanologist De Zeeuw-van Dalfsen and seismologist Sleeman was the KNMI work on Saba to monitor seismic and volcanic activity. The main conclusion was that there is no reason for concern.
Photo GIS Saba
The KNMI experts were on Saba this week to inspect and service the measuring equipment installed on different parts on the island. The KNMI has seismic equipment on the airport, in St. John’s, Windwardside and The Bottom. Also, at the first two locations Global Navigation Satellite System (GNSS) instruments are installed. A third GNSS is expected to be installed on the North Coast at a later stage. All instruments transmit the collected data to KNMI in real time.
No out of the ordinary seismic activity has been measured on Saba that could indicate a change in dormant Mount Scenery volcano. “There is no cause to be worried about the volcano,” De Zeeuw-Van Dalfsen said.
De Zeeuw-Van Dalfsen and Sleeman on Thursday installed a GPS (Global Positioning System) receiver next to the Satel building in The Bottom. The GPS receiver instrument measures its precise location on the ground, allowing to track it if the location is moving. The KNMI experts collected the data of the temperature measuring equipment at the hot spring opposite Green Island on Wednesday. No reason for alarm at the hot springs either, assured De Zeeuw-Van Dalfsen. “Everything seems to be very stable. The temperature has been a constant 82 degrees Celsius.”
The Members of the island Council posed a lot of questions to the KNMI experts. They asked in detail about the measuring and monitoring system, the occurrence of earthquakes in the region, the possibility of volcanic activity and the erosion that affects Saba.
Asked about the recent series of earthquakes near Puerto Rico, the experts explained that the situation in Puerto Rico is special because of its location near a micro plate wedged between the North American and the Caribbean tectonic plates.
The earthquakes near Puerto Rico are caused because the tectonic plates are constantly moving. The measuring equipment installed on Saba has been picking up the earthquake signals near Puerto Rico, but there is no cause for alarm locally.
De Zeeuw-Van Dalfsen and Sleeman said that people on Saba can always reach the KNMI if they have questions or if they want to report feeling a tremor or smelling a volcano-related odor. The information of the GNSS systems and seismometers on Saba, and the region, can be found online on the website www.knmidc.org
GIS Saba
There are 4 monitoring stations.
* One of them ‘SABQ – Saba – The Bottom’ is dead for more than one week, maybe much longer (see: https://www.knmi.nl/nederland-nu/seismologie/stations/live-seismogrammen).
* Station ‘SABA – Saba – St. John’ shows much activity, remarkable more than the other stations.
* Station ‘SABW – Saba – Windwardside’ showed at dec. 1 a high event and increase of activities. Before december almost no activity. Strange!
* Station ‘SABY – Saba – J. E. Y. Airport’ shows on December 4 and 5 no or almost no activity. Is the apparatus dead?
How is maintenance arranged? Why these anomalies? How often are temperature fluctuations of deep well water monitored and at what intervals?
2 out of 4 monitoring stations seem to be dead. Quite a performance of KNMI, and that in only 10 months.
Fortunately there are other scientific organizations who do perform. See the IRIS Earthquak Browser.
Thanks for your responses to this news article. As of Jan 08 2021, 3 out of 4 seismic stations and 2 out of 2 GNSS stations are operational on Saba island. That is more than for example on St. Vincent where the volcano is much more active.
Temporary hickups in life data streams are difficult to prevent and mostly due to local power outages and problems with the internet connection. In most cases when this happens data is still stored locally and retrieved when the connection is reestablished. The variations in seismic data that can be observed in lifestreams are for example due to day versus nighttime human activities on the island, and differ per site. Storms also have an impact. These anomalies are nothing unusual.
Maintenance is organised by KNMI if needed with help from SATEL. Temperature measurements at the hot-spring are collected every 20 minutes and stored locally. Data are collected whenever we are on the island and analyzed afterward.
The IRIS earthquake browser is used to locate tectonic earthquakes. For this purpose, IRIS uses data from many stations in the region, including SABA located on Saba. Our network is geared toward detecting local phenomena but also contributes to regional observations done by IRIS and the Pacific Tsunami Warning center. Please feel free to contact me (Elske) at KNMI directly (dalfsen@knmi.nl) if you have further questions.