Data indicate the magnitude 6.0 quake, which struck just after 4 a.m. local time on Sunday (May 20), just north of Bologna, was a thrust quake — the type of earthquake caused when two tectonic plates smash together — yet it occurred at a depth of just 3 miles (5 kilometers). "It is kind of surprising that it's that shallow, because it's pretty far from the plate boundary. Normally we expect things to get deeper as they move northward."
The quake hit about 470 miles (750 km) north of the plate boundary which runs along the sole of Italy's "boot." It is here that the African plate is plowing slowly northward, crashing into the Eurasian plate. The shallower a quake, the more damage it can cause. "If a quake is 500 kilometers deep, and you're right on top of it, you're going to feel it a lot less strongly than if it's 5 kilometers deep. As the seismic energy moves through the ground some of it is dissipated."
The strong quake rocked an area with a long history of earthquakes, yet one that has kept relatively quiet for hundreds of years. "There has not been a whole lot of action in that area. The fact that they do have records of earthquakes going back a couple thousand years shows this area hasn't been seismically active for a long time." Thousands of people were displaced by the quake, and many people spent the night in tents hurriedly erected on soccer fields.
After the deadly 6.3-magnitude L'Aquila earthquake in 2009, Italian officials put several Italian scientists on trial for manslaughter for not providing better warnings ahead of the deadly shaking, a move that has caused an outcry in the international scientific community. The two Italian quakes were caused by different geological mechanisms. The L'Aquila earthquake was caused when massive rock faces jerked away from one another, where as the recent earthquake was caused by their collision. Several moderate aftershocks have rocked the affected region, and it's not clear if this recent earthquake is a harbinger of things to come. "We don't know if this is going to trigger more activity in this area or not. We would expect to see aftershocks in the area for a while." There have already been at least 100 aftershocks. (map)
by being against what usually passes for it.**
Wendell Berry
LARGEST QUAKES -
Live Seismograms - Worldwide (update every 30 minutes)
This morning -
5.0 SOUTHERN PERU
Yesterday -
5/22/12 -
5.1 OFF EAST COAST OF HONSHU, JAPAN
5.1 MOLUCCA SEA
5.6 BULGARIA
5/21/12 -
5.2 OFF EAST COAST OF HONSHU, JAPAN
5.3 RYUKYU ISLANDS, JAPAN
Italy surveys damage amid dozens of aftershocks - Firefighters, surveyors, engineers and volunteers struggled through nearly continuous aftershocks Monday to catalog damage and deter looters one day after an earthquake killed seven people and left more than 6000 homeless. Photos
Japan quake aftershock tally exceeds 5000. The Sunday (May 20) quake of magnitude 6.4 would be the largest aftershock since March 14, when a magnitude-6.9 earthquake hit the region.
VOLCANOES -
Volcano Webcams
Guatemala Eruption "Largest in Years" for Fuego Volcano - Erupting Fuego Volcano has prompted alerts and flight restrictions in Guatemala near the nation's capital. An "orange" alert has been posted for Fuego, which began erupting on Saturday.
Is an eruption at Costa Rica's Turrialba Volcano imminent? - Costa Rica’s National Seismological Network has upgraded the color threat level to yellow of Turrialba Volcano, in the province of Cartago east of the capital. A threat level of yellow means that the National Seismological Network believes an eruption is “probable” in a matter of days, weeks or a few months. The upgrade in the threat level is due to “important changes in seismic activity of Volcano Turrialba associated with the movement of fluids, gas and magma beneath the surface, different from that observed in past years."
Temperatures around some fumaroles on the volcano have risen to as much as 800° Celsius, accompanied by eruptions of ash. High-temperature emissions of volcanic gases including sulfur dioxide have increased, causing incandescence in some of the fumaroles. The internal wall of the active crater is very weak due to hydrothermal changes in the volcano. This could mean a major eruption could jettison material into the atmosphere. Turrialba is the only volcano in the country currently with a yellow threat-level indicator. An upgrade to red would mean an eruptions is imminent. (photo)
Indonesia - Ailments Spread Among Refugees of Sirung Eruption. Various ailments, including coughs and other respiratory conditions, have affected hundreds of people seeking safety in temporary shelters after the eruption of Mount Sirung on Pantar island in the Eastern Nusa Tenggara District of Alor.
TROPICAL STORMS -
In the Pacific -
-Tropical Storm Bud was located about 435 mi...700 km SSW of Manzanillo Mexico.
-Tropical Storm 03w (Sanvu) was located approximately 495 nm south of Iwo To, Japan.
Tropical Storm Bud is maintaining maximum sustained winds near 40 mph amid predictions that it will strengthen and could become a hurricane by Wednesday night. Less than a week after the start of the eastern Pacific hurricane season, tbe tropical storm formed off Mexico.
Tropical Storm Sanvu passes Guam, strengthens - Tropical Depression 03W in the western North Pacific did exactly what forecasters expected over the last twenty-four hours: the tropical disturbance in the Marianas region became a tropical storm named Sanvu and passed west of Guam on a northwesterly track.
