Figure caption: Red triangles show locations of the present stations of the Malta Seismic Network. Black triangles represent planned locations of further stations.
Unexplained historical reports of “tremors” felt by the Maltese population can now be better understood thanks to the constant upgrading and extension of the Malta Seismic Network (MSN), managed by the Seismic Monitoring and Research Group (SMRG) within the Department of Geosciences. The MSN is the subject of a recently published paper “A First National Seismic Network for the Maltese Islands—The Malta Seismic Network” in the Focus Section on European Seismic Networks of the renowned journal Seismological Research Letters. The paper is available online.
Following funding from various national and international projects, the MSN now boasts eight broadband, three-component seismic stations, all transmitting their data continuously in real-time.
This data, representing the constant vibration of the Earth’s surface, is archived at a computer server hosted at the IT Services facilities, and processed automatically on a daily basis. Identified seismic events, or other signals which trigger the monitoring system, are manually verified by an analyst and made public on the SMRG website, which also serves to receive reports from the public about any felt ground shaking.
The eight stations are installed over Malta, Gozo and Comino, in a variety of locations, including church crypts, underground tunnels and historical towers, which are secure, in close coupling with the rock and having access to power. More stations are planned in the coming months and years. Data transmission is either over ADSL phone line, or via 4G modems.
The distribution of seismic stations over the archipelago means that the SMRG now has much better estimates of the epicentres of small and micro-earthquakes that occur around the islands. This is important since such seismic activity identifies active submarine faults that may contribute to the local seismic hazard. The SMRG also operates a virtual Mediterranean network by receiving real-time data from a large number of seismic stations in other countries, so that significant earthquakes and potential tsunamis in the Mediterranean region are closely monitored.
It provides rapid information to the Civil Protection Department in the case of a felt earthquake, and has recently collaborated with them in a tsunami alert drill (NEAMWave21) coordinated by the UNESCO Intergovernmental Commission for NEAMTWS (North East Atlantic and Mediterranean Tsunami Warning System.