Cyprus lies within the Alpine-Himalayan seismic zone, in which about 15% of the world earthquakes occur. The seismicity of Cyprus is thought to be due to the “Cyprus Arc”, which constitutes the tectonic boundary between the African and Eurasian in the eastern Mediterranean region. The African plate moves northwards, colliding with the Eurasian plate. As a result it is being sub-ducted (pushed under) the Anatolian microplate, which marks southern end of the Eurasian plate.
Historical references and archaeological findings reveal that strong earthquakes struck Cyprus in the past, which on several occasions destroyed its towns. Historical data show that 20 destructive earthquakes with intensities of at least “V” on the modified Mercalli scale occurred between 26 B.C. and 1900 A.D.
More accurate data of earthquakes occurring in the Cyprus region have been collected since 1896, when seismological stations started operating in neighbouring countries. The situation has improved considerably since the mid-1980s with the establishment of local seismological stations in Cyprus.
During the last century, at least 500 earthquakes with epicentres in the vicinity of the broader Cyprus area were felt in parts of the island. Out of these, 14 caused damage and some of them unfortunately caused victims. The highest seismic activity is observed in the south-west part of the Cyprus Arc and on land faults along in the south part of the island, in Pafos, Limassol and Larnaka Districts.
The study of the historical and recent earthquakes shows that the distribution in time of the seismic activity is not regular, but there are periods of intense activity followed by periods of quiescence. During the period 1995-1999, an increase of seismic activity was observed with strong to very strong earthquakes with magnitudes of 5.6-6.5 on the Richter scale.
Continuous and detailed monitoring of the seismicity of the broader area of Cyprus is done through the seismological centre of the Geological Survey Department. This centre composes of nine on-shore and two ocean-bottom seismological stations, equipped with sensitive seismometers and utilizing satellite communication technology for private real-time and continuous communication with two seismological data processing centres.
Earthquakes are natural phenomena that cannot be avoided. However, the effects of earthquakes to the built-environment can be reduced considerably or even be obliterated. In order to achieve this, measures have been taken since the 1980s that have concentrated principally on the following: a) the study and better understanding of the seismicity of the Cyprus region; b) the study of the behaviour of soils during an earthquake in which buildings and other structures are founded, with special emphasis on the soils of urban and coastal areas; c) the construction of seismic resistant structures and the anti-seismic shielding of existing ones; and d) the establishment of the necessary infrastructure for immediate and effective reaction following an earthquake.
Besides earthquakes, there are additional geohazards in Cyprus, such as landslides and soil swelling and subsidence. The most significant are landslides which are identified as destabilization of rock/soil masses on a slope and their downhill movement. Landslides may occur due to a number of factors, the most significant of which are rock/soil type and slope. However, hydrological and hydrogeological conditions as well as climate conditions, seismicity and some human intervention also contribute to landslides activation.
Favourable conditions for landslides exist mainly in areas of Pafos and Limassol Districts, where in the 1960s the communities such as Choletria, Agios Photios, Statos, Fasoula, Phinikas, Korfi, Kivides and Pentalia have been abandoned and relocated to safer areas.
As part of a comprehensive response and proper management of geohazards, the Geological Survey establishes geohazard zoning/suitability in problematic areas, especially in the Pafos District and creates relevant thematic maps, which are a useful tool for a better and safer urban development planning.
For further information:
Geological Survey Department webpage: www.moa.gov.cy/gsd
Tel: 22 409213