Seismic

SEISMIC DATA AND TSUNAMI ALERT OF THE GSMB Tel.. 2729227, Fax. 2729184 Objectives and Functions: Seismic Data and Tsunami Alert Centre (SDTAC) of the GSMB was established soon after the devastating tsunami on 26th of December 2004. One of the main objectives of this centre is to assist the authorities to issue timely tsunami warnings by monitoring the seismic activity of the Indian Ocean. The Centre receives real-time seismic data from the PALK seismic station at Pallekele, Kandy and 10 other global stations. In addition, Waveform Data from a number of stations including the stations in Cocos island, Diego Garcia, Australia are available through IDA Data Tools, as initial information. The event confirmation is based on CISN (California Integrated Seismic Network), information from USGS and Japanese Meteorology Agency. The Centre is also monitoring seismic activity in and around Sri Lanka using seismic station at Pallekele, Kandy and information received from a network of seismometers managed by the University of Peradeniya. The Centre is operating round the clock and the general public can make inquiries about tsunami threats and earthquakes/tremors at any time by calling to 0112729227. The Centre has been a very useful facility for the coastal habitants in view of eliminating their unfounded fear due to false news and rumours. The SDTAC requests the general public to report any earth tremors or unusual ground vibrations felt in various parts of the country. In this respect exact time of the event, location and true nature of the observation are important. Global Network and the Pallekele Seismic Station: In order to study and monitor the global seismicity, a network comprised of a large number of member seismic stations (seismometers) is necessary. Seismic stations at Pallekele, Kandy (PALK) is one such member seismic station of the global seismic network (GSN). This station was installed in 2000 by the University of California, San Diego in collaboration with the geological Survey and Mines Bureau. The seismometers at this station record and transmit seismic wave information to the data processing centre in California. The PALK station has made valuable contributions in monitoring the global seismicity ever since it was established in 2000. Among the key equipment at this station are Teledyne Geotech KS 54000 broadband seismometer which is emplaced in a cased borehole drilled into the migmatitic rock at a depth of 100 meters and Guralp CMG-3T which is set in a shallow borehole drilled not far (0.5 meter) from the earlier. Current Development Activities: The Geological Survey and Mines Bureau is designated as the National Seismic Data Centre by the CTBTO (Comprehensive Nuclear Test Ban Treaty Organization) and the GSMB is closely working with the CTBTO, Vienna to develop the capability of the Data Centre. A link to CTBTO has been already established via a VPN connection. Data Centre is receiving real-time data from 10 other global of seismic stations. Currently, scientists of the GSMB are being trained to accurately describe and interpret the seismic events, based on real-time data received. In order to strengthen and enhance our contributions to global seismic activity monitoring, arrangements are being made to install two (02) more broadband seisimometers under the assistance of GEOFON, Germany. A new seismic network consists of 04 short period seismometers has been proposed in order to monitor seismicity in and around Sri Lanka. Once the proposed activities are implemented, the GSMB will have full capability to detect and describe local seismic events as well as global events.