Analysing seismic occurrences in the central Mediterranean Region and relocating recent seismic events

Abstract

The Maltese Islands form part of the group of faults and rifts situated in the central Mediterranean which are termed as the Pantelleria Rift System. The subduction of the African plate beneath the Eurasian plate is responsible for the occurrence of seismic events taking place in this region. Most of the earthquakes originate from the faults in the Pantelleria Rift system, the Calabrian Arc, the Hellenic Arc and the Malta Escarpment. Data from Italian seismic networks Italian Seismic Instrumental and parametric Data-basE (ISIDe) and Centro Nazionale Terremoti (CMT), which are run by lstituto Nazionale di Geofisica e Vulcanologia (INGV), was used to analyse the occurrences of seismic events in the central Mediterranean region. From these results, it was concluded that most earthquakes in this area occur at the South-eastern coast of Sicily close to the Malta Escarpment and at the faults situated between Pantelleria and the Maltese Islands. Most of these events were shallow earthquakes with a small magnitude, mostly ranging from 2.0 to 3.0 with a focus less than 25km deep. In order to determine the location of an earthquake's epicentre, the S-P time interval and back azimuth were used to calculate the distance and angle of the event from the seismic station. LESSLA is used to automatically pick the arrival times of seismic waves and analyses the waveforms picked up by WDD. Since Seismic Monitoring and Research Unit (SMRU) in Malta uses a single-station approach to calculate an earthquake's location, the importance of using multiple stations is highlighted in this study. The importance of accurate seismic catalogs is essential for the assessment of the seismic risk and hazard of an area. Although the seismic risk in Malta is low, the seismic hazard is relatively high due to the urban growth and high population density.