The map proved prescient: The quake struck in the zone of highest hazard, which runs down the spine of the Apennine ranges of central and southern Italy.
The shaking recorded at Norcia peaked at about 0. One can only assess a probabilistic hazard map by looking at hundreds of large quakes, but if we had to judge it by this one alone, it was excellent. The map is based on the modern and ancient record of earthquakes, on the identification of active faults, and on the crustal strain measured by GPS receivers — the same constituents of the USGS seismic hazard map for the United States.
Why the quake was so damaging is an embarrassing but essential question for Italy. To calibrate the U. Shockingly, they found that if 10, people were subjected to violent shaking Modified Mercalli Intensity IX in Iran, 3, would die; in Italy, ; and in California, just three.
For a quake such as the one that struck central Italy in August , the U. Geological Survey PAGER system had projected a likely death toll between and 1, and economic losses ranging from billion to 0 billion. As of early October, those estimates held true. Credit: both: U. Geological Survey. In this quake, about 10, people were exposed to violent shaking Modified Mercalli Intensity IX and the current death toll is, sadly, consistent with their estimate.
None of these disparities are caused by differences in shaking; all are due to construction. The entire Abruzzo region was destroyed in , so many buildings date from the early s. Buildings more than a century old are typically made of heavy, unreinforced masonry or stones, and cannot resist the side-to-side shear forces exerted by even a modest quake like this one. The highest recorded ground acceleration during this quake was in Norcia, 19 kilometers from the epicenter.
The strong shaking lasted only for three to four seconds and peaked at a relatively modest 0. Well-built wood frame homes should come through this level of shaking unscathed. On the basis of damage, it is possible — but doubtful — that the shaking was much stronger at Amatrice, the town that was almost leveled.
The mainshock lies between Norcia and Amatrice, so the seismic waves traveled in both directions toward these two towns and so should be comparable.
Many friendships have been formed, and across the generations. The few inhabitants who have gone back to their homes over the past couple of years live beside cranes, diggers and dusty roads. Meticulously restructured buildings stand opposite ones still clad in scaffolding. By day, workmen help by patronising the handful of bars, restaurants and shops that have reopened. Subjects Geology Seismology.
In a region known to be seismically active, destruction on this scale was still a surprise. The village of Amatrice was devastated by the earthquake that hit central Italy. Authors Alison Abbott View author publications. View author publications. Additional information Tweet Follow NatureNews. Rights and permissions Reprints and Permissions. About this article. Cite this article Abbott, A. Copy to clipboard.
Search Search articles by subject, keyword or author. Show results from All journals This journal. Several neighbouring faults are related to extensional tectonic forces associated with the opening of the Tyrrhenian Basin to the west.
There had been several thousand foreshocks and aftershocks since December , more than thirty of which had a Richter magnitude greater than 3. Many buildings also collapsed. Approximately 1, people were injured. Twenty of the victims were children. In addition, around 65, people were made homeless. Fallen masonry resulted in many streets being blocked. The hospital where many of the injured were taken was damaged by a magnitude 4.
Approximately 40, people who were made homeless by the earthquake found accommodation in tented camps. In addition, 10, were housed in hotels on the coast. Some effects of the earthquake occurred later and indirectly as a result of the initial earthquake itself. The secondary effects included aftershocks triggering landslides and rockfalls, causing damage to housing and transport. A landslide and mudflow were caused by a burst main water supply pipeline near the town of Paganio.
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