August 27, 2011

Six aftershocks since Tuesday quake


What hurricane? I’m still thinking about earthquakes. Seismologists have recorded six aftershocks near the Mineral, Va. epicenter of Tuesday’s magnitude 5.8 tremor. A magnitude 2.8 shake followed the initial quake by less than an hour. There were two more Wednesday, and three Thursday, ranging from 2.5 to 4.5 on the Richter scale. Small shakes are common, even in the East. There were two (2.5 and 2.8) Thursday near Malone, N.Y., and one near White Sulphur Springs, W. Va.


Posted by Frank Roylance at 12:01 AM | | Comments (3)
Categories: Earthquakes

August 24, 2011

How big was Tuesday's quake?

If you've never experienced an earthquake before - and most people on the East Coast haven't - Tuesday's shaker was HUGE. It shook things that aren't ever supposed to shake, and rattled us in every sense of the word. We will all remember where we were when it struck, and we may never experience anything like it again in our lifetimes, at least not in Maryland.

But earthquakes certainly do occur in the Eastern United States. Small ones are rather common. Damage 1886 Charleston quakeMaryland's most recent one was just last summer. And there are some very big ones in the history books. So how does Tuesday's quake fit into the picture?

Charles F. Richter, of the California Institute of Technology, didn't develop his earthquake magnitude scale until 1935, so any rankings for earthquakes before that are estimates based on anecdotal reports of the shaking, and written damage accounts. (On the scale, each whole number increase reflects a 10-fold increase in measured amplitude, or shaking, and an energy release about 31 times the power of the previous whole number. 

The U.S. Geological Survey says the 5.8 quake near Mineral, Va. on Tuesday was nearly as strong as the estimated magnitude 5.9 shaking in May 1897 centered in Giles County, in southwestern Virginia. The Giles County quake is regarded as the strongest on record for Virginia. That makes Tuesday's quake the strongest Virginia earthquake in 114 years.1886 Charleston quake damage

Much like the Mineral quake, and many Eastern earthquakes, the Giles County quake was felt far from the epicenter  - from Pennsylvania to Georgia, and from the Atlantic to Indiana and Kentucky, according to the USGS. The walls of old brick houses were cracked, bricks broke off chimneys, and clear springs turned muddy. Aftershocks were felt in June, September and October of that year.

But the Mineral quake was a long way from being the strongest to strike the East Coast since we began keeping records. That distinction goes to the Great Earthquake of 1886, the one that nearly leveled Charleston, S.C. (photos) That one is estimated to have been a magnitude 7.3 on the Richter Scale.

The Charleston earthquake was felt strongly in Baltimore, as were the New Madrid, Mo. quakes in 1811-1812. 

Tuesday's earthquake occurred in the Central Virginia Seismic Zone. The strongest quake on record there before this week was an estimated 4.5 shake in 1875. So yesterday's event can be said to be the strongest there in 136 years.


Posted by Frank Roylance at 1:27 PM | | Comments (6)
Categories: Earthquakes

August 23, 2011

Yes, that was an earthquake

The tremor occurred at about 1:51 p.m. It was given a preliminary magnitude of 5.8, centered about 35 miles northwest of Richmond. We are evacuating our building, but leave a comment and we will post when we return.

UPDATE, 6:30 p.m.: Well, we're back, and nearly the entire newsroom is working quake-related stories. I've just filed one on the geo-science behind Eastern quakes, with help from Jeff Halka ant the Maryland geological Survey and Michael Scott, a professor of geography and geo-science at Salisbury University.

It turns out today's quake was the largest on record for Virginia, and one of the largest ever felt in Maryland. It was also the strongest of five so far today around the globe of magnitude 5.0 or higher.

The others included a mag. 5.3 in Colorado, and three others in the Fiji Islands of the Pacific; on the Kashmir/India border; and in Papua, New Guinea.


Posted by Frank Roylance at 2:01 PM | | Comments (29)
Categories: Earthquakes

May 26, 2011

Loaded propane tanker was imperiled by tsunami

Here's a terrifying story that seems to have escaped telling in the wake of the horrific-enough tsunami in Japan back in March.

Kashima port after quakeThe Maritime Professional website tells the harrowing tale of Capt. Mukesh Yadav and the 754-foot long liquified propane tanker Flanders Tenacity. The ship was in port at Kashima on March 11. It was waiting to unload 23,500 tons of liquid propane when the captain, in his cabin, felt the ship shake.

Concerned that someone had started the engines without authorization, he rushed out to discover it was an earthquake. Worse, a tsunami was expected within minutes. The prospect that his ship might be wrecked, and spill its cargo of propane across the port or explode set him to work in a frantic bid to get the ship out of the harbor.

He called for tugs, but the port was being abandoned ahead of the tsunami.  And when the waves began to toss the ship about, a collision with a jetty put a gash in the hull. Water poured in and threatened to submerge the compressors that kept the propane cold and under control. Electricity from the shore was knocked out by the earthquake.

It gets worse. Read the rest of the story here.

(PHOTO: Kashima port after quake, Toru Yamanaka, AFP/Getty Images)  

Posted by Frank Roylance at 3:44 PM | | Comments (0)
Categories: Earthquakes

March 11, 2011

Japan quake felt in Virginia water well

The big earthquake this morning in Japan sent seismic waves around the planet, and, as so often happens with big quakes, those waves triggered a reacting in an especially quake-sensitive monitoring well in Christiansburg, Va. Take a look at the seismic tracing below.

The quake caused the 2.5-foot rise and fall in the water level in the USGS well, visible in the blue spike on the right. And sizable tremors continue to rattle the epicenter off the coast on Honshu.

And here's a pretty nifty visual on how the tsunami propagated across the Pacific.

Japan earthquake water well


Posted by Frank Roylance at 10:40 AM | | Comments (0)
Categories: Earthquakes

November 30, 2010

Mag. 3.9 quake reported off Delmarva

New quake mapThe U.S. Geological Survey is reporting a Mag. 3.9 undersea earthquake at about 10:45 a.m. Tuesday, centered off the continental shelf 181 miles southeast of New York City. That's roughly 200 miles east northeast of Ocean City, MD.

The tremor occured an estimated 5 km beneath the ocean bottom. It was reportedly felt by residents of Long Island. Anyone on Delmarva feel this one? Leave a comment and let us know.

UPDATE: The USGA has revised the initial report. Geologists now say the quake was 122 miles east southeast of New York City, and 189 miles northeast of Ocean City, Md., at the edge of the continental shelf and 6 km beneath the surface.

(USGS map)

Posted by Frank Roylance at 11:17 AM | | Comments (12)
Categories: Earthquakes

July 16, 2010

Yes, it was an earthquake


The US Geological Survey is reporting a 3.6 magnitude shaker at 5:04 a.m. EDT today, centered in the Gaithersburg area. That's pretty minor, but unusual for Maryland and quite enough to be felt across much of Central Maryland, as the map suggests. 

UPDATE: Here is the current Sun story on the quake.

I had this report this morning from Brian Heinz, in Columbia:

"I was sleeping and felt the bed shaking and felt as if the house was shaking as well.  When I came to, I looked at my Verizon cable box and the clock said 5:05. I immediately thought it was an earthquake or a plane going overhead, because of the noise.  I feel like the earthquake actually made noise or it was the house shaking.

"I went back to bed and just woke up and checked the USGS earthquake map. An earthquake happened at 5:04 am in the Potomac/Shenandoah Region. AWESOME.

"Finally met one of my three random goals in life. Feel an earthquake, see a tornado, and be in a hurricane."

Steve Zubrick, the science officer at the National Weather Service forecast office in Sterling, Va., sent this:

"Big news down here. I felt the house shook as it woke me out of a dead sleep just after 5 am."

Any one else?  Leave a comment.

There are some details from the USGS about this here. And here's more on the history of earthquakes in Maryland. And here's a little on the most recent quake reported in Maryland, just outside of Baltimore, in 2007.

Posted by Frank Roylance at 7:14 AM | | Comments (40)
Categories: Earthquakes

June 3, 2010

Small tremor 57 miles NNW of Baltimore


The U.S. Geological Survey is reporting a small earth tremor Thursday morning just 57 miles north northwest of Baltimore. The Mag. 2.9 shake occurred at 8:25 a.m. EDT northeast of Franklintown, Pa., and 14 miles south southwest of Harrisburg.

USGS reported the quake was very shallow, centered less than a mile below the surface. 

Here's more on  the history of earthquakes in Pennsylvania.

Anyone out there feel this jiggle? Leave us a comment and describe it.

Posted by Frank Roylance at 10:21 AM | | Comments (2)
Categories: Earthquakes

April 20, 2010

Small quake in E. Tenn. recalls 1973 event

A small, Mag. 3.3 tremor south of Knoxville, Tenn. this morning calls to mind a similar quake in the same area in 1973 that turned out to be a precursor of a larger 4.6 quake that caused some damage in the Maryville, Tenn. area short time later.

USGSThis morning's shake occured at 5:28 a.m. The epicenter was 5 miles west southwest of Maryville, and 19  miles west southwest of Knoxville. The Knoxville News Sentinel this morning quoted residents who said they were shaken awake by the tremor.

“I woke to the loud boom here in Maryville and then felt the shaking and heard the windows and doors rattle,” Jennifer Cahan wrote in an e-mail to the newspaper. “My 7 pound dog promptly crawled under the covers."

It is an area of considerable seismic activity, although all of the recent shakes have been small. Western Tennessee, on the other end of the state from this morning's tremor, is in the New Madrid fault zone, one of the most worrisome seismic areas in the nation. A tremendous series of quakes there in 1811-1812 was felt across the eastern half of the nation. A repeat today could be expected to do serious damage in places such as Memphis and St. Louis.

On Oct. 30, 1973, a tremor measured at Mag. 3.6 shook the Maryville area. It was followed by a Mag. 4.6 "main shock" that caused minor damage in nearby parts of Tennessee, Georgia, North Carolina and Kentucky. Walls cracked, and windows and chimneys were damaged. The 1973 shake was also felt in parts of Virginia, West Virginia and South Carolina.

As of 10:30 a.m. EDT, there has been no further shaking in Tennessee since this morning's tremor.

UPDATE Thursday 11 a.m.: The USGS has reported another, smaller tremor near Maryville, at 10:14 p.m. Wednesday night.

Posted by Frank Roylance at 10:10 AM | | Comments (0)
Categories: Earthquakes

January 13, 2010

Va. well reacts to Haiti quake; aftershocks continue

The US. Geological Survey continues to monitor seismic events in Haiti in the wake of last evening's terrible 7.0 quake just outside the capital of Port-au-Prince. At last check, the country had sustained at least 34 aftershocks of magnitude 4.5 to 5.9.

Other faults in the region have also been active. There was a magnitude 2.5 tremor early today in the Mona Passage between Hispaniola and Puerto Rico. And the Virgin Islands reported a 3.2 shake late last night.

The powerful quake in Haiti registered strongly in a water well in Christiansburg, in southwestern Virginia, operated by the Va. Department of Environmental Quality and monitored by the USGS.

The well is very sensitive to seismic waves passing through the Earth, and water levels will rise and fall sharply in response to large quakes around the world. Here (below) is the tracing of the well's water levels in the past few days. The Haiti quake is reflected in the sharp spike - more than 9 inches - on Jan. 12.

USGS officials in Baltimore said they have seen no similar response to the quake in water wells monitored in Maryland or Delaware. (No word from dog owners. Here's how one pooch reacted seconds BEFORE the recent quake off the Northern California coast.)

USGS well in Christianburg, Va. 

Posted by Frank Roylance at 11:32 AM | | Comments (1)
Categories: Earthquakes

January 12, 2010

Earthquakes common in Caribbean

This evening's devastating 7.0 earthquake in Haiti has been followed by a series of large aftershocks measuring more than 5.0 on the Richter scale. It was also preceded by  smaller quakes (2.9 to 3.4) in Puerto Rico, across the Mona Passage from the island Haiti shares with the Dominican Republic. Here's more news from Haiti.

USGSAlthough it is not as familiar as the Pacific's seismically and volcanically active "Ring of Fire," the Caribbean Islands also lie on an active fault system. Earthquakes, volcanoes and tsunamis are all facts of life in the islands, past and present.

The much-visited port of Charlotte Amalie, in the U.S. Virgin Islands, was the scene of a devastating tsunami in 1867 that sent a 20-foot wall of water surging in to the harbor. Large U.S. Naval ships were beached by the waves. Other Caribbean ports also felt the tsunami.

Another large quake (magnitude 7.5) in October 1918 struck Puerto Rico. It killed more than 100 people, caused widespread damage, and sent a tsunami as high as 20 feet ashore.

An earthquake in Jamaica in 1692 destroyed the port city of Kingston, and dropped it into the sea. More than 5,000 people died. Jamaicans felt the Tuesday evening quake in Haiti, too.

The most famous volcanic event in the Caribbean was the 1902 eruption of Mt. Pele, on theMonserrat ash flow French island of Martinique.  Now regarded as the deadliest volcanic eruprtion of the 20th century, it killed nearly all 30,000 residents of the capital, Saint-Pierre.

One of the two survivors lived because he was in a poorly ventilated jail cell.

On the island of Monserrat (right), the Soufriere Hills volcano has been in some state of eruption since 1995, when it destroyed the capital town of Plymouth. Two-thirds of the island's population was forced to leave. Here's a recent satellite photo.

(AP PHOTO/Brennan Linsley, 2006)

Posted by Frank Roylance at 6:01 PM | | Comments (16)
Categories: Earthquakes

December 7, 2009

Small quake Sunday southeast of Atlanta

USGSThe U.S. Geological Survey is reporting a small earthquake at about 7:27 p.m. EST Sunday 13 miles from Milledgeville, Ga., southeast of Atlanta. The very shallow tremor was measured at Magnitude 3.2.

Eastern Georgia and especially South Carolina have been the sites of numerous small, and a few very big earthquakes over the past few centuries.

An 1886 quake in Charleston, S.C. killed scores of people, did tremendous damage and was felt as far away as Boston, Bermuda, Chicago and Cuba.

Here are some details on last night's tremor. Here are some more maps.

And here is some information about the history of earthquakes in Georgia.

Posted by Frank Roylance at 10:39 AM | | Comments (0)
Categories: Earthquakes

October 25, 2009

Did you feel it? Earth tremor in Franklintown, Pa.


The Earth quivered a bit this morning up near Franklintown, Pa., about 58 miles north northwest of Baltimore. It was a small one, with a magnitude of just 2.8. recorded by the U.S. Geological Survey at 7:21 a.m. Sunday.

Here are some more details on the tremor. And here is a bit on the history of quakes in Pennsylvania.

Quakes this size are barely perceptible, even close to the epicenter. No damage would be expected. But if you're in the region and felt something, drop us a comment and describe where you were, the time, what you were doing and what you felt. You should also report it to the USGS, here

Posted by Frank Roylance at 8:25 AM | | Comments (0)
Categories: Earthquakes

August 14, 2009

Small quake jiggles SW Virginia

Virginia quakeA small earth tremor, rated with a magnitude of 2.5, shook portions of southwestern Virginia at about 9:48 a.m. today.

UPDATE: This tremor has been revised upward, to a 2.9

The epicenter (red dot on the map at left)was placed about 2 miles northeast of Nickelsville, which is northwest of Bristol, Tenn. The shake originated with movement about 3 miles below the surface.

Here is a map of recent seismicity in Virginia.

And here is a history of Virginia quakes.

Posted by Frank Roylance at 11:20 AM | | Comments (0)
Categories: Earthquakes
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This site is the Maryland Weather archive. The current Maryland Weather blog can be found here.
Frank Roylance is a reporter for The Baltimore Sun. He came to Baltimore from New Bedford, Mass. in 1980 to join the old Evening Sun. He moved to the morning Sun when the papers merged in 1992, and has spent most of his time since covering science, including astronomy and the weather. One of The Baltimore Sun's first online Web logs, the Weather Blog debuted in October 2004. In June 2006 Frank also began writing comments on local weather and stargazing for The Baltimore Sun's print Weather Page. Frank also answers readers’ weather queries for the newspaper and the blog. Frank Roylance retired in October 2011. Maryland Weather is now being updated by members of The Baltimore Sun staff

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