Abruzzo (Italy) Earthquake

Update 1 | Summary
Posting Date: April 7, 2009, 7:00:00 PM

AIR estimates that insured losses from Monday’s magnitude 6.3 earthquake that struck the Abruzzo region of Italy are likely to range between €200 million and €400 million. Industry losses are being limited by the low earthquake take-up rates in the region. Insurable, or ground up, losses from this event are estimated at between €2-3 billion. As a point of reference, Monday’s earthquake occurred roughly 100 km from a magnitude 6.0 earthquake that struck the Umbria-Marche region in 1997, killing 11 people. That quake has been characterized by Italy's National Institute of Geophysics and Volcanology and the USGS as “similar” to the event that occurred Monday. According to a 2004 report from AXCO, the 1997 event caused an estimated USD4.5 billion in economic losses and $90 million in insured losses. According to a paper published in 2002 by A. Goretti and G. Di Pasquale of Italy's Department of Civil Protection, 100,000 buildings were inspected in the aftermath of that event and 27,000 (27%) were judged to be unusable. As of Tuesday, April 7, the death toll from Monday’s earthquake has risen to 235. More than 5,000 rescue workers continue to sift through rubble in the hope of finding survivors, but continuing aftershocks, including a magnitude 5.6 in the village of Fossa this evening, are hampering those efforts. The initial earthquake seems to have weakened some buildings making them more vulnerable to the aftershocks. While the geographic extent of damage was fairly limited—to L’Aquila and nearby villages—the severity of damage within the affected area was high. The results of a 2005 study published in the Bulletin of the Seismological Society of America suggest the potential for strong ground-motion amplification effects at low frequencies in L’Aquila due to the presence of a sedimentary basin bounded to the north by a northwest-southeast trending normal fault. Downtown L’Aquila is situated on a fluvial terrace that forms the left bank of the Aterno River. Fortunately, the faulting mechanism for Monday’s earthquake was normal, a mechanism that generally produces lower levels of ground motion compared to strike-slip or reverse faulting. Several dozens of instruments are located in the area, though no accelerograms have yet been published. An estimated 15,000 buildings were damaged in Monday’s quake and tens of thousands of people have had to leave their homes while inspections are underway. In the nearby village of Onna, virtually every home was damaged or destroyed. Forty people out of a population of 300 were killed. Similar levels of destruction were reported in the nearby village of Tempera. Italy’s Civil Protection Department is in the process of putting up 7,000 tents in and around L'Aquila, with the capacity to sleep 40,000. The historic center of L’Aquila has been devastated. As expected, damage to unreinforced masonry (URM) buildings is severe. Narrow streets have been made impassable by the rubble of collapsed URM houses—many of them more than 100 years old. However, damage was not restricted to the oldest structures. Many non-ductile reinforced concrete (RC) frame buildings dating from the 1960s and 1970s—and thus predating seismic code provisions—suffered heavy damage as well. Among these, the variability of damage is reported to be high, with one severely damaged next to another which appears to be intact. Several of these structures collapsed, including a four-story apartment building and the headquarters of the national government’s regional representative. However, even newer RC frame buildings also suffered damage, and many exhibit gaping shear cracks in their walls. The city’s main hospital, which was inaugurated in 2000, was partially closed because of damage. Following the catastrophic M6.9 Irpinia earthquake that killed 3,000 people in 1980, the Italian Government launched a research effort to advance the understanding of seismic hazard in the country. Construction codes were introduced that were intended to ensure that new construction would withstand ground shaking similar to that produced by Monday’s earthquake. The codes were updated most recently in early 2008 to reflect the latest seismic hazard map published by Italy's National Institute of Geophysics and Volcanology (INGV). Undoubtedly, many questions will now be raised regarding code enforcement and the pace at which older buildings are retrofitted. The AIR earthquake team has analyzed the available information about the earthquake using the AIR Earthquake Model for the Mediterranean Region. Loss estimates and maps are now posted on the Scenarios page of the ALERT website, and event sets are available for download. AIR estimates that insured losses from this event are likely to range between € 200 million and €400 million. Note that these estimates include losses to residential, commercial and industrial buildings and contents. They do not include Business Interruption losses. The estimated take-up rates (the percentage of properties that actually carry earthquake insurance) for the region are approximately 5% for residential and 35% for commercial and industrial. However, it should be noted that there is considerable uncertainty around take-up rates in the affected region. CATRADER® users should be aware that adjustments to the industry loss estimates have been made to account for the current exchange rate and an approximately 18% increase in industry-wide exposure values in the region during the last several years. As a result loss estimates generated in CATRADER may differ from those found in this summary. AIR will be sending a reconnaissance team to the affected area once search and rescue operations have ceased.

Update 1 | Downloads
Posting Date: April 7, 2009, 7:00:00 PM