RMS, AIR Analyze Greek Quake

Risk Management Solutions and AIR Worldwide have both issued bulletins analyzing the effects of a 6.1 magnitude earthquake that struck Western Greece at 03:26 p.m. local time on Sunday, June 8.

RMS said that according to “preliminary reports from the US Geological Survey (USGS), the epicenter was around 20 miles (35 kms) southwest of Patras and 125 miles (200 kms) west of Athens, with a depth of 6.2 miles (10 km).”

AIR Worldwide’s report on the quake noted that the “shock was felt as far away as Italy.” The quake reportedly killed two people, and injured nearly 150. It also “leveled about 70 houses in the provinces of Ahaia and Ilia and severely damaged 260 more,” said AIR.

AIR’s Senior research engineer Guillermo Franco explained: “The worst damage is likely to be restricted to un-reinforced masonry residential structures, which are unlikely to be covered by earthquake insurance. Greece is highly prone to earthquakes. Seismicity here is governed by the interactions of three major tectonic plates: the Eurasian, African, and Arabian plates. The motions of these major plates drive smaller plates, such as the Aegean Sea plate in southern Greece, the movement of which determines the locations and focal mechanisms of most of the earthquakes in this region.

“The Aegean Sea plate, for example, is moving southwest relative to the Eurasia plate at a velocity of about 30mm/year [app 1/8 inch], and the subduction of the Africa plate beneath this plate dominates the seismotectonics of southern Greece.”

Another prominent feature of tectonic origin along the west coast of Greece is the Cephalonia Transform fault (CTF)—a strike-slip fault with a slip rate of 20-30 mm/yr. Franco commented, “The epicenter of Sunday’s earthquake was less than 100km to the east of the CTF,” Franco continued. “Since 1700, seventy earthquakes with magnitude exceeding 5.0 have occurred within a 50 km radius of yesterday’s epicenter. Thirteen of those were of magnitude 6 or greater.”

Dr. Andrew Sorby, model manager for Europe earthquake at RMS, noted that there had been “numerous aftershocks, the largest of which was a magnitude 4.7, and we may see more in the next few days.” He indicated that the “worst affected settlements include the villages of Valmi, Fostaina and the town of Kato Achaia.’

Sorby also expalined: “Other earthquakes to have affected this part of Greece include the M6.0 Kyllini earthquake in 1988 and an earthquake in 1806 in Patras, which caused 53 fatalities. Greece and the surrounding region is the most seismically active part of Europe. The region is part of a broad and complex boundary zone between the Eurasian, African and Anatolian Plates.”

Sources: Risk Management Solutions – www.rms.com; AIR Worldwide- www.airworldwide.com