Syzdekistan

When I wrote about the earthquake on February 21, I noted that the Modified Mercalli Intensity (MMI) rating of VI might be low: “Looking at the damage in Wells, I wonder if this be upgraded a bit once seismologist takes a look at the damage.”

A MMI of VI can be expected to be “Strong.”

“Felt by all; many frightened and run outdoors, walk unsteadily. Windows, dishes, glassware broken; books off shelves; some heavy furniture moved or overturned; a few instances of fallen plaster. Damage slight.”

However, news reports stated that most homes had some damage and some buildings had major damage. Many of the old downtown buildings completely lost their facades and fell onto the street.

While there have been no reports of homes totally collapsing, some foundations and support beams or joists cracked. Chimneys throughout the town collapsed during the earthquake, sometimes falling onto and damaging roofs This afternoon, Reinschmidt visited the home of Sally Huston, a 61-year-old retiree who lives in a manufactured home. The earthquake collapsed a porch roof and caused the home’s frame to separate a few inches at the apex, but the home is livable.
“I don’t know what I’m hoping,” Huston said. “I have no idea what it will cost me.”
Kim Toulouse, an inspector for the Nevada Division of Emergency Management and a spokesman for the agency, said some homeowners have been reporting major damage to their home. But when inspectors arrive, Toulouse said, they find only minor repairs are needed.
Even so, Toulouse said minor damage can seem like a catastrophe to some.
“A lot of time, what my job is is to let people vent,” she said.
A few businesses opened today, including the gas stations and the town’s largest casino.
The Red Cross has established a shelter at the Wells’ elementary school. Down the street, the town’s junior and senior high school is closed indefinitely due to major damage. ” (Link)

Today I printed out the very nice USGS poster about the Wells Nevada earthquake and sure enough the MMI has been upped to a VII: “Very Strong.”

Difficult to stand; furniture broken; damage negligible in building of good design and construction; slight to moderate in well-built ordinary structures; considerable damage in poorly built or badly designed structures; some chimneys broken. Noticed by persons driving motor cars.

There has been very little coverage of the earthquake in the Las Vegas press. The Salt Lake City Tribune has had some good coverage.

I’ve only driven through past Wells a few times but do remember it is in a typical Nevada basin. Perhaps the original Mercalli rating was a little low because the town sits in a valley of basin fill material that amplified the motion of the earthquake. The USGS just calculated the expected scale from the magnitude (Richter), depth of the focus, and location of the earthquake. Then when the damage reports came in, they adjusted the scale.

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