Monday, April 6, 2009

Italian Seismic Destruction.

Felt Reports

At least 150 people killed, 1500 injured and 10,000 buildings damaged or destroyed in the L' Aquila area. Felt throughout central Italy.

Tectonic Summary
The April 6th 2009 earthquake in Central Italy occurred as a result of normal faulting on a NW-SE oriented structure in the central Apennines, a mountain belt that runs from the Gulf of Taranto in the south to the southern edge of the Po basin in northern Italy. Geologically, the Apennines are largely an accretionary wedge formed as a consequence of subduction. This region is tectonically and geologically complex, involving both subduction of the Adria micro-plate beneath the Apennines from east to west, continental collision between the Eurasia and Africa plates building the Alpine mountain belt further to the north and the opening of the Tyrrhenian basin to the west. The evolution of this system has caused the expression of all different tectonic styles acting at the same time in a broad region surrounding Italy and the central Mediterranean. The April 6th, 2009 earthquake is related to normal faulting and the east-west extensional tectonics that dominate along the entire Apennine belt, primarily a response to the Tyrrhenian basin opening faster than the compression between the Eurasian and African plates.

The central Apennine region has experienced several significant earthquakes in recorded history. In 1997, a significant Mw 6.0 earthquake 85 km north-northwest of the April 6th 2009 event killed 11, injured over 100 and destroyed approximately 80,000 homes in the Marche and Umbria regions. This 1997 event was part of a series of earthquakes known as the Umbria-Marche seismic sequence, which included eight events of magnitude greater than M5.0 in a two-month period between September and November of that year.

Experts Watching Eruption of Italy's Stromboli Volcano
Wednesday, February 28, 2007

Feb. 27: Plumes of smoke are seen coming out of the Stromboli island volcano during eruptive activity, some 40 miles north of Sicily, Italy.

ROME — Lava continued to pour down Stromboli's slopes and into the Mediterranean near Sicily Wednesday as experts continued to monitor eruption activity on one of Europe's most active volcanoes.

Experts taking helicopter flights over Stromboli and studying data from monitoring devices studding the volcano's slopes said there was no immediate danger to the few hundred residents of the tiny island, 40 miles northeast of Sicily.

Stromboli, which on most days belches smoke and flaming lava and rock from its crater, suddenly started spewing a substantial amount of lava into the sea on Tuesday, prompting authorities to warn islanders about the risk of a small tidal wave.

Islanders were told to evacuate homes that are below 33 feet above sea level as a precaution.

"The situation is absolutely under control," Civil Protection chief Guido Bertolaso told journalists on the island after an aerial survey Wednesday.

Ferries and hydrofoils which link Stromboli and the six other islands in the Aeolian archipelago were operating, he noted.

Italy's Stromboli Volcano Erupts In late 2002, Stromboli experienced a rare effusive eruption — an outpouring of lava without the volcano's characteristic explosive activity, which was its first in 17 years. A few days later, landslides tumbled down an uninhabited slope, crashing into the sea and setting off a tidal wave.

In spring 2003, Stromboli sent hardened lava raining down on some of the settlements nestled in the folds of the island's green slopes. A few chunks crashed into houses.

Parts of Italy's south are marked by volcanic activity. Besides Stromboli, Mount Etna in eastern Sicily bubbles back to life every few months. Experts have been worried about Vesuvius, the volcano which devastated ancient Pompeii in 79 A.D. and which now towers above villages ringing its slopes and the metropolis of Naples.

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