More shaking before the sixth seal (Revelation 6:12)

Report: New York City is overdue for a major earthquake

If a 5.0 Earthquake were to hit New York City, there could be $39 billion dollars worth of damage and 30 million tons of rubble… and experts say the city is overdue, according to the Daily Mail. Veuer’s Sam Berman has the full story.

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Believe it or not, the Rochester region has experienced two small earthquakes in five days.

One was last Friday, the other Tuesday. Both were centered several miles below Lake Ontario, less than 100 miles away. Neither did any damage and almost no one felt them.

Still, we’re having a San Andreas moment. Here’s what you need to know about it:

Are two quakes in five days unusual?

No, not at all. There have been 46 temblors in the state in the last two years. That’s one every two weeks. Massena and Malone, neighboring small cities in the North Country, have alone recorded six quakes since Christmas.

These two under Lake Ontario just pushed the envelope a little.

Could the two temblors be related?

Actually, yes.

“Thirty years ago … we would have said it’s just coincidence, one has nothing to do with another. But that view has changed,” John Tarduno, a professor of geophysics at the University of Rochester, told us Tuesday.

Today’s thinking is a quake could relieve stress in one fault zone but increase it in neighboring faults, he said.

Countless fractures and faults exist in the Earth’s crust below New York state. Some are clustered in fault zones.

Tarduno, who chairs UR’s earth and environmental sciences department, said our back-to-back quakes probably weren’t on the same fault. More likely, they were on parallel north-south faults that run under the lake.

Movement along the fault under the central part of Lake Ontario, where last week’s tiny temblor occurred, could have impacted a fault farther west, providing the impetus for Tuesday’s quake.

What causes our quakes?

Not exactly the same thing that causes severe earthquakes in places like California.

There, the problem is the collision of the nine immense continent-sized plates of rock that underlie the Earth’s surface. The plates shift slowly en masse, but sometimes one plate becomes wedged against another.

Earthquakes occur along the West Coast and other plate boundaries when the plates finally break free of one another, releasing pent-up energy. (Think of an overweight canine trying to squeeze through a tight doggie door. When he finally bursts through, he’s likely to go head over heels.)

There are no doggie doors here in upstate New York. We’re in the middle of the North American plate, not at the edge. So what happens here?

Tarduno said the ever-moving plates impart energy to neighboring plates. Here, it could be the Atlantic impacting the North American plate. It’s like a chain-reaction accident on a crowded highway — one car slams in the back of another, which slams another, which slams a third. Pretty soon, the 20th car in line has a crumpled back end.

When that energy reaches the large cracks known as faults that exist in the crust in the interior of the continent, those faults can slip. Bingo, another small earthquake.

Does this happen everywhere?

Rochester and the area just to our west and southwest, where there is a well-known fault zone known as the Clarendon-Linden, are in a low-to-moderate earthquake hazard zone. It’s the fourth-worst of seven long-term hazard levels assigned by the U.S. Geological Survey.

New York City, the Hudson Valley and much of northern New York are in the fourth level, reflecting the more extensive fault zones that exist there. The extreme northeastern corner of the state is the most seismically active place in the Northeast, and was assigned the fifth hazard level.

Large sections of the country — the Upper Midwest and Plains, much of Texas and Florida — have little or no long-term risk of earthquakes, according to the Geological Survey.

Has New York ever had a really bad quake?

No, there is no record of a truly awful earthquake in New York — the kind that levels entire blocks and leaves many people injured or dead.

However, at least six earthquakes centered in New York state have measured above magnitude 5.0 — the level at which people are frightened and some damage to property can occur.

What likely was the second-worst quake in state history occurred shortly after 6 a.m. Aug. 12, 1929, and was centered near Attica, Wyoming County. It was felt throughout western and central New York, Pennsylvania and Ontario. Its magnitude has been estimated at 5.2 to 5.6.

In Attica, chimneys fell, walls cracked, windows shattered and people panicked. In Rochester, some buildings were felt to sway and unsecured dishes shattered on the floor.

The worst quake in state history, with a magnitude of 5.8 to 6.0, struck shortly after midnight Aug. 5, 1944. Centered near Massena, St. Lawrence County, the quake was felt throughout New York, New England and adjoining areas of Quebec and Ontario.

Damage was extensive in Massena and nearby Cornwall, Ontario. In Rochester, many residents leaped from their beds, and dishes and windows rattled.

No injuries were reported in either quake.

How could someone in Victor feel Tuesday’s quake when you didn’t?

It’s the luck of the draw.

One local person reported feeling Tuesday’s earthquake to the Geological Survey. In 2013, a more powerful quake 200 miles away in Canada led more than 250 Monroe County residents to file an “I felt it” report with the agency. A strong 2011 quake in Virginia, 350 miles distant, triggered more than 500 local reports.

Large earthquakes are felt by everyone. Smaller ones? It depends on where you are and what you’re doing.

“The proximity (of the quake), the type of building you’re living in, how the energy propagates through the crust, all these things come into play,” Tarduno said.

“Think about this: Take a wine glass and hit it with your finger. The glass may ring, or the glass may not ring. Buildings are that way,” he said. “It just happens to be the oddities of how the energy focuses so that even with a small earthquake, people might feel it more one place more than another. It’s how the energy interacts with your surroundings.”

People on upper floors are more likely to feel a building’s movement. People in a quiet room are more likely to notice.

Those who are outside are less likely to sense anything amiss. As Tarduno noted, there are numerous accounts of people strolling a sidewalk oblivious to a sizable quake and wondering why everyone else is rushing into the street.

Are worse quakes coming?

Last week’s temblor was magnitude 1.5. This week’s was a 2.4. Does this mean that we’ll hit 3.6 next week?

“It doesn’t work that way,” Tarduno said with a laugh. “There’s no relationship in terms of size.

“I think this wasn’t an unusual event, given the historic seismicity that we know about the area,” he said.

SORR@Gannett.com

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