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MINERAL, Va. (AP) — When the “Big One” rocked the East Coast one year ago, the earthquake centered on this rural Virginia town cracked ceiling tiles and damaged two local school buildings so badly that they had to be shuttered for good. Now as the academic year gets under way, students are reciting a new safety mantra: Drop, cover, and hold on.
Earthquake drills are now as ubiquitous as fire drills at Louisa County schools in central Virginia, where 4,600 students were attending classes when the 5.8-magnitude quake struck nearby on Aug. 23, 2011. Miraculously, no one was seriously hurt.
“It’s the new normal,” Superintendent Deborah D. Pettit said of the earthquake drills. “It’s become a normal part of the school routine and safety.”
One such drill is planned for Thursday at 1:51 p.m. EDT — the precise moment a year ago when the quake struck.
The unexpected jolt cracked the Washington Monument in spots and toppled delicate masonry high atop the National Cathedral. The shaking was felt far along the densely populated Eastern seaboard from Georgia to New England.
While West Coast earthquake veterans scoffed at what they viewed as only a moderate temblor, last year’s quake has changed the way officials along the East Coast view emergency preparedness.
Emergency response plans that once focused on hurricanes, tornadoes, flooding and snow are being revised to include quakes. Some states have enacted laws specifically related to the quake, and there is anecdotal evidence of a spike in insurance coverage for earthquake damage.
The quake was centered 3 to 4 miles beneath Mineral, a town of fewer than 500 people about 50 miles northwest of Richmond. Yet it was believed to have been felt by more people than any other in U.S. history.
The damage, estimated at more than $200 million, extended far beyond rural Louisa County. In the nation’s capital, the Washington Monument sustained several large cracks and remains closed indefinitely.
The National Park Service plans next month to finalize the contract to repair the Washington Monument. Repairs are expected to cost $15 million and require a massive scaffolding, and the landmark obelisk is likely to remain closed until 2014.
The National Cathedral reopened last November, but repairs are expected to take years and cost $20 million. The cathedral announced Thursday that it has received a $5 million grant from the Indianapolis-based Lilly Endowment Inc. With that funding in place, stonemasons were scheduled to begin active restoration Thursday afternoon. Previously, they had been stabilizing the damaged components and cataloging the damage.
In Virginia, the North Anna Power Station became the first operating U.S. nuclear power plant shut down because of an earthquake.
Was it a once-in-a-century anomaly, or are there more quakes to come?
Scientists are trying to answer that question as they pore over the data and survey the epicenter from the air.
According to the U.S. Geological Survey, much of central Virginia has been labeled for decades as an area of elevated seismic hazard. But last year’s quake was the largest known to occur in that seismic zone.
“Scientists would like to know if this earthquake was Virginia’s ‘Big One,’” said J. Wright Horton of the USGS.
Meanwhile, the quake prompted several jurisdictions to revise their emergency response plans.
“We learned a lot, that’s for sure,” said Laura Southard, a spokeswoman for the Virginia Department of Emergency Management. One lesson, she said: the need to conduct post-quake assessments to size up damage.
Ultimately, 6,400 homeowners and renters in nine Virginia localities received $16.5 million from the Federal Emergency Management Agency.
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Volcanic Activity
BY: T
Photographs of the inner crater inside the outer crater, the presence of magma inside the inner crater and pyroclastic deposits in the crater. (S. Vallejo and MF. Naranjo, OVT-IGEPN)
Small pyroclastic flow on the western flank of the volcano in the afternoon of August 21, 2012 (IGEPN)
Thermal image of the continuous emission of gases and ash accompanied by expulsion of incandescent material (Source: S. Vallejo, OVT-IG)
Thermal image of the northern flank of the volcano with fresh pyroclastic deposits and the trace of the lava flow recorded on Saturday August 18 (S. Vallejo, OVT-IGEPN)
Current seismic signal (RETU station, IG)
Tremor signal on current seismic recording (RETU station, IG)
SO2 plume from Tungurahua yesterday 21 Aug (NOAA)
Tungurahua’s eruption continues. This morning, a tall ash plume was rising to 32,000 ft (ca. 10 km) altitude and drifting west. A slight decrease in tremor is visible on the latest seismograms.
So far, effects of the eruption have been limited to ash fall. In canton Quero, the ash fall during the past days has damaged more than 5000 hectares of plant cultivations and hit about 2.000 families.
In the meanwhile, scientists from the volcano observatory have made an overflight of the volcano and posted the following interesting update (freely translated) for 20-21 Aug:
The volcano emits a neary constant eruption column, associated with explosions, that reached a maximum height of 5 km and an average height of 1.5 km above the crater, with moderate ash content, drifting to the west. There were no new reports of ash fall.
An increase in the number and size of the explosions was observed since 15:00 local time on 20 Aug. Until 16:00 on 21 Aug, there were 16 large explosions producing strong cannon-shot noises heard in villages near the volcano and in cities as far away as Ambato, Riobamba and Miracle.
The seismic activity at Tungurahua shows a constant tremor signal associated with steam, gas and ash emissions.
Otherwise, the roaring noises have decreased in intensity and duration with respect to the previous days.
In the evening observatory staff observed constant expulsion of hot material in jets. Lava blocks landed outside the crater and rolled up to 1.5 km from the top of the volcano’s flanks.
An explosion at 14:11 on 21 Aug generated an ash column rising 4 km above the crater, that produced a small pyroclastic flow that descended approximately 2.5 km along the Achupashal creek.
Staff of the Geophysical Institute of the National Polytechnic School conducted an overflight of the volcano yesterday afternoon for thermal and visual monitoring of the activity in the crater area and top of the mountain. They observed that that much of the western and southwestern flank have been covered by fresh ash and blocks.
Thermal images show near continuous explosive activity from the inner crater, ejecting incandescent material onto the the upper flanks of the volcano, where temperatures ranged between 116 and 150°C.
The morphology of the summit consists of an outer crater containing an inner crater about 80 m wide, and a few dozend meters distance from the outside crater. The inner crater was observed to be almost filled with fresh lava. Numerous large meter sized hot blocks could be identified in the crater area and the upper flanks. Temperatures measured at the crater raned between 550°C for the inner crater and 236°C at the outer crater.
Many fresh lava blocks have accumulated in ravines on the south-west, west and north-west upper flanks of the volcano. These could be mobilized to form avalanches IG scientists warn.
The thermal image analysis confirmed that during the night of Saturday, August 18, a lava flow and an incandescent avalanche of blocks that had accumulated in the north-western flank flew down through the Cusu canyon as had been observed then.
IG recommends the authorities and the general public to maintain protective and preparative measures in case the activity escalates further which is a possibility. Most danger during the ongoing activity comes from pyroclastic flows, lahars and ash fall.
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Links / Sources:
New 9.com
MessageToEagle.com – New dangerous cracks in ground appeared on our planet.
