USGS Evidence Shows Power of the Sixth Seal (Revelation 6:12)

New Evidence Shows Power of East Coast Earthquakes
Virginia Earthquake Triggered Landslides at Great Distances
Released: 

11/6/2012 8:30:00 AM USGS.gov

Earthquake shaking in the eastern United States can travel much farther and cause damage over larger areas than previously thought.

U.S. Geological Survey scientists found that last year’s magnitude 5.8 earthquake in Virginia triggered landslides at distances four times farther—and over an area 20 times larger—than previous research has shown.

“We used landslides as an example and direct physical evidence to see how far-reaching shaking from east coast earthquakes could be,”

said Randall Jibson, USGS scientist and lead author of this study. “Not every earthquake will trigger landslides, but we can use landslide distributions to estimate characteristics of earthquake energy and how far regional ground shaking could occur.”

“Scientists are confirming with empirical data what more than 50 million people in the eastern U.S. experienced firsthand: this was one powerful earthquake,” said USGS Director Marcia McNutt. “Calibrating the distance over which landslides occur may also help us reach back into the geologic record to look for evidence of past history of major earthquakes from the Virginia seismic zone.”

This study will help inform earthquake hazard and risk assessments as well as emergency preparedness, whether for landslides or other earthquake effects.

This study also supports existing research showing that although earthquakes  are less frequent in the East, their damaging effects can extend over a much larger area as compared to the western United States.

The research is being presented today at the Geological Society of America conference, and will be published in the December 2012 issue of the

Bulletin of the Seismological Society of America.

The USGS found that the farthest landslide from the 2011 Virginia earthquake was 245 km (150 miles) from the epicenter. This is by far the greatest landslide distance recorded from any other earthquake of similar magnitude. Previous studies of worldwide earthquakes indicated that landslides occurred no farther than 60 km (36 miles) from the epicenter of a magnitude 5.8 earthquake.

“What makes this new study so unique is that it provides direct observational evidence from the largest earthquake to occur in more than 100 years in the eastern U.S,” said Jibson. “Now that we know more about the power of East Coast earthquakes, equations that predict ground shaking might need to be revised.”

It is estimated that approximately one-third of the U.S. population could have felt last year’s earthquake in Virginia, more than any earthquake in U.S. history.

About 148,000 people reported their ground-shaking experiences caused by the earthquake on the USGS “Did You Feel It?” website. Shaking reports came from southeastern Canada to Florida and as far west as Texas.

In addition to the great landslide distances recorded, the landslides from the 2011 Virginia earthquake occurred in an area 20 times larger than expected from studies of worldwide earthquakes. Scientists plotted the landslide locations that were farthest out and then calculated the area enclosed by those landslides. The observed landslides from last year’s Virginia earthquake enclose an area of about 33,400 km2

, while previous studies indicated an expected area of about 1,500 km2

from an earthquake of similar magnitude.

“The landslide distances from last year’s Virginia earthquake are remarkable compared to historical landslides across the world and represent the largest distance limit ever recorded,” said Edwin Harp, USGS scientist and co-author of this study. “There are limitations to our research, but the bottom line is that we now have a better understanding of the power of East Coast earthquakes and potential damage scenarios.”

The difference between seismic shaking in the East versus the West is due in part to the geologic structure and rock properties that allow seismic waves to travel farther without weakening.

Learn more

about the 2011 central Virginia earthquake.

New 3.6 earthquake felt before the Sixth Seal: Revelation 6

New 3.6 earthquake felt in South Carolina, strongest one in 8 years

This was the second stronger earthquake in the central South Carolina region Wednesday.

COLUMBIA, S.C. — Another earthquake has shaken much of the Midlands, just hours after another strong tremor rattled the area.

The U.S. Geological Survey says the 3.6 magnitude quake struck at 7:03 p.m. Wednesday about 1.24 miles east of Elgin. It was at a depth of just a tenth of a mile, which is very close to the surface for an earthquake.

The USGS has confirmed two aftershocks, both at 7:22pm. One was 1.5 magnitude and the other was 1.8 magnitude. The two aftershocks happed at different times in the same minute.   

It was the seventh quake of the day. 

This week has seen 12 earthquakes. 

News19 has gotten reports of people feeling the earthquake throughout the central Midlands and up near the Charlotte area. At WLTX, we were on the air when the 3.6 quake took place and that moment was captured on-air.

Watch Below: The moment when the earthquake struck at News19 

The later tremor a bit stronger than the one that took place just hours earlier. The earlier one was a 3.5 magnitude quake that happened at 2:43 p.m. in an area 3.2 miles east of Elgin. The USGS shake map got well over 3,000 reports of people feeling it, with reports all across Richland, Kershaw, and Lexington Counties and has far north as Charlotte.  

The Kershaw County Emergency Management division says the power outages in the area were caused by the earthquake.  The earthquake triggered the switch plates which caused the power to blink off for a while. 

Three much smaller aftershocks also took place. 

Earthquakes happen throughout the state but most occur near the coast. Approximately 70 percent of earthquakes are in the coastal plain, with most happening in the Lowcountry. 

Back in 1886, Charleston was hit by a catastrophic earthquake. It had an estimated magnitude of 7.3, and was felt as far away and Cuba and New York. At least 60 people were killed, and thousands of building were damaged.

Structural damage extended hundreds of miles to cities in Alabama, Ohio, and Kentucky.

Geologists say that Charleston lies in one of the most seismically active areas in the eastern United States.

More Shaking Before the Sixth Seal: Revelation 6

For the 21st time this week, earthquakes hit the Columbia by I area

By Noah FeitUpdated July 03, 2022 12:16 PM

Two more earthquakes were confirmed in the Columbia area early Sunday morning as seismic activity continued following a recent series of relatively powerful earthquakes.

Sunday’s 1.9 and 1.6 magnitude earthquakeswere the 20th and 21st to hit the Midlands in the past week, according to the South Carolina Department of Natural Resources Geological Survey.

The first earthquake, recorded at a depth of 2.1 kilometers, or about 1.3 miles, was reported within 3 miles of Elgin at 12:16 a.m., the South Carolina Emergency Management Division said. The second hit about 2 miles beneath the surface in the area closer to Lugoff at 6:29 a.m., according to the U.S. Geological Survey.

“In case you were wondering if it was fireworks or earthquakes earlier this morning …” SCEMD said on Facebook.

While it would normally be no competition between the amount of vibrations caused by fireworks on a Fourth of July holiday weekend in South Carolina and the shaking felt from an earthquake’s tremors, the question is legitimate this year because of all the recent seismic activity.

Last Sunday, an earthquake was recorded in Elgin, according to the USGS. That led a series of earthquakes, or aftershocks, including a pair of 3.5 magnitude and 3.6 magnitude quakes on Wednesday afternoon and early evening.

Those were the two largest quakes to hit South Carolina in nearly a decade. A 4.1-magnitude quake struck McCormick County in 2014. 

Another earthquake in Georgia on June 18 reached a 3.9 magnitude and could be felt in much of South Carolina.

The recent earthquakes mean at least 50 have been detected in the Palmetto State since the start of 2022, according to South Carolina DNR. All but five of the quakes have been in the Midlands.

In all, 52 earthquakes have hit the Columbia area since a 3.3 magnitude quake was recorded on Dec. 27, 2021, according to the South Carolina Department of Natural Resources.

No major damage or injuries have been reported from any of the recent quakes.

Earthquakes that register 2.5 magnitude or less often go unnoticed and are usually only recorded by a seismograph, according to Michigan Technological University. Any quake less than 5.5 magnitude is not likely to cause significant damage, the school said.

It is typical for South Carolina to have between six and 10 earthquakes a year, the S.C. Geological Survey previously reported. There have been 77 earthquakes in South Carolina since Jan. 18, 2021, according to the S.C. Department of Natural Resources.

An explanation for the recent outburst has eluded scientists

Digging and blasting at mines, water seeping through the ground from lakes, or other changes in weight or pressure underground could all contribute to seismic activity, The State previously reported, but no one has settled on the single cause for the Midlands’ shaking. The state Department of Health and Environmental Control said last week that mining activity is not likely to be the cause of recent earthquakes, as mines in the Elgin area are shallow.

Elgin, located about 20 miles northeast of Columbia and situated on a fault line, has been experiencing an unusual earthquake “swarm” for the past several months, leaving some residents feeling uneasy. The series of quakes might be the longest period of earthquake activity in the state’s history, officials said last week. But officials have said they don’t believe the spate of minor earthquakes is an indicator that a bigger quake could be on the way.

The strongest earthquake ever recorded in South Carolina — and on the East Coast of the U.S. — was a devastating 7.3 in Charleston in 1886.

That quake killed 60 people and was felt over 2.5 million square miles, from Cuba to New York, and Bermuda to the Mississippi River, according to the Emergency Management Division.

Reported earthquakes in SC in 2021-22

Date/Location

Magnitude

Depth (km)

Jan. 18/Dalzell

2.1

6.9

Feb. 13/Summerville

2.1

5.1

May 12/Heath Springs

1.8

9.99

May 31/Summit

2.6

1.7

May 31/Summit

2.05.1

July 16/Ladson2.04.0

July 22/Ladson1.3

3.5

July 22/Ladson

1.95

3.97

Aug. 21/Centerville

1.75

1.97

Aug. 21/Centerville

1.71

3.37

Sept. 27/Summerville2.86.0

Sept. 27/Summerville

2.0

5.8

Sept. 27/Centerville

3.36.8Oct. 25/Jenkinsville2.23.8Oct. 26/Jenkinsville1.80.0Oct. 28/Jenkinsville1.81.8Oct. 28/Jenkinsville1.70.0Oct. 28/Jenkinsville2.14.2Oct. 31/Jenkinsville2.30.1Nov. 1/Jenkinsville2.05.1Nov. 9/Centerville1.53.8Nov. 16/Arial2.25.4Dec. 20/Ladson1.12.8Dec. 27/Lugoff3.33.2Dec. 27/Lugoff2.52.4Dec. 27/Elgin2.10.7Dec. 27/Lugoff1.74.9Dec. 29/Elgin2.31.6Dec. 30/Elgin2.52.5Dec. 30/Elgin2.43.8Jan. 3/Lugoff2.52.7Jan. 5/Lugoff2.60.5Jan. 5/Lugoff1.57.0Jan. 9/Ladson1.42.9Jan. 11/Elgin1.75.4Jan. 11/Lugoff2.03.2Jan. 11/Elgin1.35.0Jan. 15/Elgin1.83.5Jan. 19/Elgin1.95.0Jan. 21/Elgin1.94.8

Jan. 27/Lugoff2.11.0Feb. 2/Elgin1.53.9March 4/Elgin1.82.8March 9/Elgin2.23.6March 11/Camden2.11.2March 27/Lugoff2.11.9March 28/Centerville0.92.9April 7/Elgin2.02.9April 8/Centerville1.63.6April 22/Ladson1.13.5April 22/Taylors2.22.3May 9/Elgin3.33.1May 9/Elgin1.62.9May 9/Elgin1.784.1May 9/Elgin2.13.7May 9/Elgin2.95.6May 10/Elgin2.33.9May 10/Elgin2.86.2May 19/Elgin1.82.5May 21/Elgin1.95.6June 26/Elgin1.884.09June 29/Elgin3.52.64June 29/Elgin1.882.92June 29/Elgin3.62.95June 29/Elgin1.792.07June 29/Elgin1.513.72June 29/Elgin1.461.93June 29/Elgin2.062.22June 30/Elgin2.323.09June 30/Elgin1.442.8June 30/Elgin2.033.11June 30/Elgin2.152.56June 30/Elgin2.061.92June 30/Elgin1.492.46July 1/Elgin1.553.37July 1/Elgin2.113.83July 1/Elgin1.263.3July 1/Elgin1.684.02July 2/Elgin2.091.65July 3/Elgin1.92.1July 3/Lugoff1.63.2

USGS Evidence Shows Power of the Sixth Seal (Revelation 6:12)

New Evidence Shows Power of East Coast Earthquakes
Virginia Earthquake Triggered Landslides at Great Distances
Released: 

11/6/2012 8:30:00 AM USGS.gov

Earthquake shaking in the eastern United States can travel much farther and cause damage over larger areas than previously thought.

U.S. Geological Survey scientists found that last year’s magnitude 5.8 earthquake in Virginia triggered landslides at distances four times farther—and over an area 20 times larger—than previous research has shown.

“We used landslides as an example and direct physical evidence to see how far-reaching shaking from east coast earthquakes could be,”

said Randall Jibson, USGS scientist and lead author of this study. “Not every earthquake will trigger landslides, but we can use landslide distributions to estimate characteristics of earthquake energy and how far regional ground shaking could occur.”

“Scientists are confirming with empirical data what more than 50 million people in the eastern U.S. experienced firsthand: this was one powerful earthquake,” said USGS Director Marcia McNutt. “Calibrating the distance over which landslides occur may also help us reach back into the geologic record to look for evidence of past history of major earthquakes from the Virginia seismic zone.”

This study will help inform earthquake hazard and risk assessments as well as emergency preparedness, whether for landslides or other earthquake effects.

This study also supports existing research showing that although earthquakes  are less frequent in the East, their damaging effects can extend over a much larger area as compared to the western United States.

The research is being presented today at the Geological Society of America conference, and will be published in the December 2012 issue of the

Bulletin of the Seismological Society of America.

The USGS found that the farthest landslide from the 2011 Virginia earthquake was 245 km (150 miles) from the epicenter. This is by far the greatest landslide distance recorded from any other earthquake of similar magnitude. Previous studies of worldwide earthquakes indicated that landslides occurred no farther than 60 km (36 miles) from the epicenter of a magnitude 5.8 earthquake.

“What makes this new study so unique is that it provides direct observational evidence from the largest earthquake to occur in more than 100 years in the eastern U.S,” said Jibson. “Now that we know more about the power of East Coast earthquakes, equations that predict ground shaking might need to be revised.”

It is estimated that approximately one-third of the U.S. population could have felt last year’s earthquake in Virginia, more than any earthquake in U.S. history.

About 148,000 people reported their ground-shaking experiences caused by the earthquake on the USGS “Did You Feel It?” website. Shaking reports came from southeastern Canada to Florida and as far west as Texas.

In addition to the great landslide distances recorded, the landslides from the 2011 Virginia earthquake occurred in an area 20 times larger than expected from studies of worldwide earthquakes. Scientists plotted the landslide locations that were farthest out and then calculated the area enclosed by those landslides. The observed landslides from last year’s Virginia earthquake enclose an area of about 33,400 km2

, while previous studies indicated an expected area of about 1,500 km2

from an earthquake of similar magnitude.

“The landslide distances from last year’s Virginia earthquake are remarkable compared to historical landslides across the world and represent the largest distance limit ever recorded,” said Edwin Harp, USGS scientist and co-author of this study. “There are limitations to our research, but the bottom line is that we now have a better understanding of the power of East Coast earthquakes and potential damage scenarios.”

The difference between seismic shaking in the East versus the West is due in part to the geologic structure and rock properties that allow seismic waves to travel farther without weakening.

Learn more

about the 2011 central Virginia earthquake.

East Coast Quakes and the Sixth Seal: Revelation 6

Items lie on the floor of a grocery store after an earthquake on Sunday, August 9, 2020 in North Carolina.

East Coast Quakes: What to Know About the Tremors Below

By Meteorologist Dominic Ramunni Nationwide PUBLISHED 7:13 PM ET Aug. 11, 2020 PUBLISHED 7:13 PM EDT Aug. 11, 2020

People across the Carolinas and Mid-Atlantic were shaken, literally, on a Sunday morning as a magnitude 5.1 earthquake struck in North Carolina on August 9, 2020.

Centered in Sparta, NC, the tremor knocked groceries off shelves and left many wondering just when the next big one could strike.

Fault Lines

Compared to the West Coast, there are far fewer fault lines in the East. This is why earthquakes in the East are relatively uncommon and weaker in magnitude.

That said, earthquakes still occur in the East.

According to Spectrum News Meteorologist Matthew East, “Earthquakes have occurred in every eastern U.S. state, and a majority of states have recorded damaging earthquakes. However, they are pretty rare. For instance, the Sparta earthquake Sunday was the strongest in North Carolina in over 100 years.”

While nowhere near to the extent of the West Coast, damaging earthquakes can and do affect much of the eastern half of the country.

For example, across the Tennesse River Valley lies the New Madrid Fault Line. While much smaller in size than those found farther west, the fault has managed to produce several earthquakes over magnitude 7.0 in the last couple hundred years.

In 1886, an estimated magnitude 7.0 struck Charleston, South Carolina along a previously unknown seismic zone. Nearly the entire town had to be rebuilt.

Vulnerabilities

The eastern half of the U.S. has its own set of vulnerabilities from earthquakes.

Seismic waves actually travel farther in the East as opposed to the West Coast. This is because the rocks that make up the East are tens, if not hundreds, of millions of years older than in the West.

These older rocks have had much more time to bond together with other rocks under the tremendous pressure of Earth’s crust. This allows seismic energy to transfer between rocks more efficiently during an earthquake, causing the shaking to be felt much further.

This is why, during the latest quake in North Carolina, impacts were felt not just across the state, but reports of shaking came as far as Atlanta, Georgia, nearly 300 miles away.

Reports of shaking from different earthquakes of similar magnitude.

Quakes in the East can also be more damaging to infrastructure than in the West. This is generally due to the older buildings found east. Architects in the early-to-mid 1900s simply were not accounting for earthquakes in their designs for cities along the East Coast.

When a magnitude 5.8 earthquake struck Virginia in 2011, not only were numerous historical monuments in Washington, D.C. damaged, shaking was reported up and down the East Coast with tremors even reported in Canada.

Unpredictable

There is no way to accurately predict when or where an earthquake may strike.

Some quakes will have a smaller earthquake precede the primary one. This is called a foreshock.

The problem is though, it’s difficult to say whether the foreshock is in fact a foreshock and not the primary earthquake. Only time will tell the difference.

The United State Geological Survey (USGS) is experimenting with early warning detection systems in the West Coast.

While this system cannot predict earthquakes before they occur, they can provide warning up to tens of seconds in advance that shaking is imminent. This could provide just enough time to find a secure location before the tremors begin.

Much like hurricanes, tornadoes, or snowstorms, earthquakes are a natural occuring phenomenon that we can prepare for.

The USGS provides an abundance of resources on how to best stay safe when the earth starts to quake.

A Small Shake Before the Sixth Seal: Revelation 6

The United States Geological Survey reports a small earthquake in Louisa County.
The United States Geological Survey reports a small earthquake in Louisa County.(USGS)

Small earthquake recorded in Louisa County

By NBC12 Newsroom

Published: May. 30, 2022 at 3:37 PM MDT|Updated: 21 hours ago

LOUISA Co., Va. (WWBT) – The United States Geological Survey reports a small earthquake in Louisa County.

The quake happened on Monday, May 30 shortly after 10 a.m.

The 1.6 magnitude earthquake happened about 7 miles southwest of Louisa and about 40 miles from Richmond.

This earthquake is one of a few earthquakes recorded this spring in Virginia:

Real Risk, Few Precautions (Revelation 6:12)

         By WILLIAM K. STEVENS

Published: October 24, 1989
AN EARTHQUAKE as powerful as the one that struck northern California last week could occur almost anywhere along the East Coast, experts say. And if it did, it would probably cause far more destruction than the West Coast quake.
The chances of such an occurrence are much less in the East than on the West Coast. Geologic stresses in the East build up only a hundredth to a thousandth as fast as in California, and this means that big Eastern quakes are far less frequent. Scientists do not really know what the interval between them might be, nor are the deeper-lying geologic faults that cause them as accessible to study. So seismologists are at a loss to predict when or where they will strike.
But they do know that a temblor with a magnitude estimated at 7 on the Richter scale – about the same magnitude as last week’s California quake – devastated Charleston, S.C., in 1886. And after more than a decade of study, they also know that geologic structures similar to those that caused the Charleston quake exist all along the Eastern Seaboard.
For this reason, ”we can’t preclude that a Charleston-sized earthquake might occur anywhere along the East Coast,” said David Russ, the assistant chief geologist of the United States Geological Survey in Reston, Va. ”It could occur in Washington. It could occur in New York.”
If that happens, many experts agree, the impact will probably be much greater than in California.Easterners, unlike Californians, have paid very little attention to making buildings and other structures earthquake-proof or earthquake-resistant. ”We don’t have that mentality here on the East Coast,” said Robert Silman, a New York structural engineer whose firm has worked on 3,800 buildings in the metropolitan area.
Moreover, buildings, highways, bridges, water and sewer systems and communications networks in the East are all older than in the West and consequently more vulnerable to damage. Even under normal conditions, for instance, water mains routinely rupture in New York City.
The result, said Dr. John Ebel, a geophysicist who is the assistant director of Boston College’s Weston Observatory, is that damage in the East would probably be more widespread, more people could be hurt and killed, depending on circumstances like time of day, and ”it would probably take a lot longer to get these cities back to useful operating levels.”
On top of this, scientists say, an earthquake in the East can shake an area 100 times larger than a quake of the same magnitude in California. This is because the earth’s crust is older, colder and more brittle in the East and tends to transmit seismic energy more efficiently. ”If you had a magnitude 7 earthquake and you put it halfway between New York City and Boston,” Dr. Ebel said, ”you would have the potential of doing damage in both places,” not to mention cities like Hartford and Providence.
Few studies have been done of Eastern cities’ vulnerability to earthquakes. But one, published last June in The Annals of the New York Academy of Sciences, calculated the effects on New York City of a magnitude 6 earthquake. That is one-tenth the magnitude of last week’s California quake, but about the same as the Whittier, Calif., quake two years ago.
The study found that such an earthquake centered 17 miles southeast of City Hall, off Rockaway Beach, would cause $11 billion in damage to buildings and start 130 fires. By comparison, preliminary estimates place the damage in last week’s California disaster at $4 billion to $10 billion. If the quake’s epicenter were 11 miles southeast of City Hall, the study found, there would be about $18 billion in damage; if 5 miles, about $25 billion.
No estimates on injuries or loss of life were made. But a magnitude 6 earthquake ”would probably be a disaster unparalleled in New York history,” wrote the authors of the study, Charles Scawthorn and Stephen K. Harris of EQE Engineering in San Francisco.
The study was financed by the National Center for Earthquake Engineering Research at the State University of New York at Buffalo. The research and education center, supported by the National Science Foundation and New York State, was established in 1986 to help reduce damage and loss of life from earthquakes.
The study’s postulated epicenter of 17 miles southeast of City Hall was the location of the strongest quake to strike New York since it has been settled, a magnitude 5 temblor on Aug. 10, 1884. That 1884 quake rattled bottles and crockery in Manhattan and frightened New Yorkers, but caused little damage. Seismologists say a quake of that order is likely to occur within 50 miles of New York City every 300 years. Quakes of magnitude 5 are not rare in the East. The major earthquake zone in the eastern half of the country is the central Mississippi Valley, where a huge underground rift causes frequent geologic dislocations and small temblors. The most powerful quake ever known to strike the United States occurred at New Madrid, Mo., in 1812. It was later estimated at magnitude 8.7 and was one of three quakes to strike that area in 1811-12, all of them stronger than magnitude 8. They were felt as far away as Washington, where they rattled chandeliers, Boston and Quebec.
Because the New Madrid rift is so active, it has been well studied, and scientists have been able to come up with predictions for the central Mississippi valley, which includes St. Louis and Memphis. According to Dr. Russ, there is a 40 to 63 percent chance that a quake of magnitude 6 will strike that area between now and the year 2000, and an 86 to 97 percent chance that it will do so by 2035. The Federal geologists say there is a 1 percent chance or less of a quake greater than magnitude 7 by 2000, and a 4 percent chance or less by 2035.
Elsewhere in the East, scientists are limited in their knowledge of probabilities partly because faults that could cause big earthquakes are buried deeper in the earth’s crust. In contrast to California, where the boundary between two major tectonic plates creates the San Andreas and related faults, the eastern United States lies in the middle of a major tectonic plate. Its faults are far less obvious, their activity far more subtle, and their slippage far slower. 
Any large earthquake would be ”vastly more serious” in the older cities of the East than in California,  said Dr. Tsu T. Soong, a professor of civil engineering at the State University of New York at Buffalo who is a researcher in earthquake-mitigation technology at the National Center for Earthquake Engineering Research. First, he said, many buildings are simply older, and therefore weaker and more  vulnerable to collapse. Second, there is no seismic construction code in most of the East as there is in California, where such codes have been in place for decades.
The vulnerability is evident in many ways. ”I’m sitting here looking out my window,” said Mr. Silman, the structural engineer in New York, ”and I see a bunch of water tanks all over the place” on rooftops. ”They are not anchored down at all, and it’s very possible they would fall in an earthquake.”
 Many brownstones, he said, constructed as they are of unreinforced masonry walls with wood joists between, ”would just go like a house of cards.” Unreinforced masonry, in fact, is the single most vulnerable structure, engineers say. Such buildings are abundant, even predominant, in many older cities. The Scawthorn-Harris study reviewed inventories of all buildings in Manhattan as of 1972 and found that 28,884, or more than half, were built of unreinforced masonry. Of those, 23,064 were three to five stories high.
Buildings of reinforced masonry, reinforced concrete and steel would hold up much better, engineers say, and wooden structures are considered intrinsically tough in ordinary circumstances. The best performers, they say, would probably be skyscrapers built in the last 20 years. As Mr. Silman explained, they have been built to withstand high winds, and the same structural features that enable them to do so also help them resist an earthquake’s force. But even these new towers have not been provided with the seismic protections required in California and so are more vulnerable than similar structures on the West Coast.
Buildings in New York are not generally constructed with such seismic protections as base-isolated structures, in which the building is allowed to shift with the ground movement; or with flexible frames that absorb and distribute energy through columns and beams so that floors can flex from side to side, or with reinforced frames that help resist distortion.
”If you’re trying to make a building ductile – able to absorb energy – we’re not geared to think that way,” said Mr. Silman.
New York buildings also contain a lot of decorative stonework, which can be dislodged and turned into lethal missiles by an earthquake. In California, building codes strictly regulate such architectural details.
Manhattan does, however, have at least one mitigating factor: ”We are blessed with this bedrock island,” said Mr. Silman. ”That should work to our benefit; we don’t have shifting soils. But there are plenty of places that are problem areas, particularly the shoreline areas,” where landfills make the ground soft and unstable.
As scientists have learned more about geologic faults in the Northeast, the nation’s uniform building code – the basic, minimum code followed throughout the country – has been revised accordingly. Until recently, the code required newly constructed buildings in New York City to withstand at least 19 percent of the side-to-side seismic force that a comparable building in the seismically active areas of California must handle. Now the threshold has been raised to 25 percent.
New York City, for the first time, is moving to adopt seismic standards as part of its own building code. Local and state building codes can and do go beyond the national code. Charles M. Smith Jr., the city Building Commissioner, last spring formed a committee of scientists, engineers, architects and government officials to recommend the changes.
”They all agree that New York City should anticipate an earthquake,” Mr. Smith said. As to how big an earthquake, ”I don’t think anybody would bet on a magnitude greater than 6.5,” he said. ”I don’t know,” he added, ”that our committee will go so far as to acknowledge” the damage levels in the Scawthorn-Harris study, characterizing it as ”not without controversy.”
For the most part, neither New York nor any other Eastern city has done a detailed survey of just how individual buildings and other structures would be affected, and how or whether to modify them.
”The thing I think is needed in the East is a program to investigate all the bridges” to see how they would stand up to various magnitudes of earthquake,” said Bill Geyer, the executive vice president of the New York engineering firm of Steinman, Boynton, Gronquist and Birdsall, which is rehabilitating the cable on the Williamsburg Bridge. ”No one has gone through and done any analysis of the existing bridges.”
In general, he said, the large suspension bridges, by their nature, ”are not susceptible to the magnitude of earthquake you’d expect in the East.” But the approaches and side spans of some of them might be, he said, and only a bridge-by-bridge analysis would tell. Nor, experts say, are some elevated highways in New York designed with the flexibility and ability to accommodate motion that would enable them to withstand a big temblor.
Tunnels Vulnerable
The underground tunnels that carry travelers under the rivers into Manhattan, those that contain the subways and those that carry water, sewers and natural gas would all be vulnerable to rupture, engineers say. The Lincoln, Holland, PATH and Amtrak tunnels, for instance, go from bedrock in Manhattan to soft soil under the Hudson River to bedrock again in New Jersey, said Mark Carter, a partner in Raamot Associates, geotechnical engineers specializing in soils and foundations.
Likewise, he said, subway tunnels between Manhattan and Queens go from hard rock to soft soil to hard rock on Roosevelt Island, to soft soil again and back to rock. The boundaries between soft soil and rock are points of weakness, he said.
”These structures are old,” he said, ”and as far as I know they have not been designed for earthquake loadings.”
Even if it is possible to survey all major buildings and facilities to determine what corrections can be made, cities like New York would then face a major decision: Is it worth spending the money to modify buildings and other structures to cope with a quake that might or might not come in 100, or 200 300 years or more?
”That is a classical problem” in risk-benefit analysis, said Dr. George Lee, the acting director of the Earthquake Engineering Research Center in Buffalo. As more is learned about Eastern earthquakes, he said, it should become ”possible to talk about decision-making.” But for now, he said, ”I think it’s premature for us to consider that question.”

USGS Evidence Shows Power of the Sixth Seal (Revelation 6:12)

New Evidence Shows Power of East Coast Earthquakes
Virginia Earthquake Triggered Landslides at Great Distances
Released: 

11/6/2012 8:30:00 AM USGS.gov

Earthquake shaking in the eastern United States can travel much farther and cause damage over larger areas than previously thought.

U.S. Geological Survey scientists found that last year’s magnitude 5.8 earthquake in Virginia triggered landslides at distances four times farther—and over an area 20 times larger—than previous research has shown.

“We used landslides as an example and direct physical evidence to see how far-reaching shaking from east coast earthquakes could be,”

said Randall Jibson, USGS scientist and lead author of this study. “Not every earthquake will trigger landslides, but we can use landslide distributions to estimate characteristics of earthquake energy and how far regional ground shaking could occur.”

“Scientists are confirming with empirical data what more than 50 million people in the eastern U.S. experienced firsthand: this was one powerful earthquake,” said USGS Director Marcia McNutt. “Calibrating the distance over which landslides occur may also help us reach back into the geologic record to look for evidence of past history of major earthquakes from the Virginia seismic zone.”

This study will help inform earthquake hazard and risk assessments as well as emergency preparedness, whether for landslides or other earthquake effects.

This study also supports existing research showing that although earthquakes  are less frequent in the East, their damaging effects can extend over a much larger area as compared to the western United States.

The research is being presented today at the Geological Society of America conference, and will be published in the December 2012 issue of the

Bulletin of the Seismological Society of America.

The USGS found that the farthest landslide from the 2011 Virginia earthquake was 245 km (150 miles) from the epicenter. This is by far the greatest landslide distance recorded from any other earthquake of similar magnitude. Previous studies of worldwide earthquakes indicated that landslides occurred no farther than 60 km (36 miles) from the epicenter of a magnitude 5.8 earthquake.

“What makes this new study so unique is that it provides direct observational evidence from the largest earthquake to occur in more than 100 years in the eastern U.S,” said Jibson. “Now that we know more about the power of East Coast earthquakes, equations that predict ground shaking might need to be revised.”

It is estimated that approximately one-third of the U.S. population could have felt last year’s earthquake in Virginia, more than any earthquake in U.S. history.

About 148,000 people reported their ground-shaking experiences caused by the earthquake on the USGS “Did You Feel It?” website. Shaking reports came from southeastern Canada to Florida and as far west as Texas.

In addition to the great landslide distances recorded, the landslides from the 2011 Virginia earthquake occurred in an area 20 times larger than expected from studies of worldwide earthquakes. Scientists plotted the landslide locations that were farthest out and then calculated the area enclosed by those landslides. The observed landslides from last year’s Virginia earthquake enclose an area of about 33,400 km2

, while previous studies indicated an expected area of about 1,500 km2

from an earthquake of similar magnitude.

“The landslide distances from last year’s Virginia earthquake are remarkable compared to historical landslides across the world and represent the largest distance limit ever recorded,” said Edwin Harp, USGS scientist and co-author of this study. “There are limitations to our research, but the bottom line is that we now have a better understanding of the power of East Coast earthquakes and potential damage scenarios.”

The difference between seismic shaking in the East versus the West is due in part to the geologic structure and rock properties that allow seismic waves to travel farther without weakening.

Learn more

about the 2011 central Virginia earthquake.

A Warning of the Sixth Seal: Revelation 6:12

2.4 magnitude earthquake rattles southern New Jersey: USGS

Kristine Garcia

TUCKERTON, N.J. — A small earthquake rattled parts of southern New Jersey Wednesday morning.

The U.S. Geological Survey said the 2.4 magnitude quake occurred just before 8 a.m. about two miles from Tuckerton, New Jersey in Ocean County and about 15 miles away from Atlantic City. 

Roughly 100 people reported feeling the earthquake, with most of the reports coming from nearby Little Egg Harbor Township. 

The earthquake is the first one reported in New Jersey in more than six months. A 2.1 magnitude quake was reported in western New Jersey near Pennsylvania in December. 

Light shaking was felt, but there were no reports of injuries or damage.null

Associated Press contributed to this report.

A Warning of the Sixth Seal: Revelation 6:12

2.4 magnitude earthquake rattles southern New Jersey: USGS

Kristine Garcia

TUCKERTON, N.J. — A small earthquake rattled parts of southern New Jersey Wednesday morning.

The U.S. Geological Survey said the 2.4 magnitude quake occurred just before 8 a.m. about two miles from Tuckerton, New Jersey in Ocean County and about 15 miles away from Atlantic City. 

Roughly 100 people reported feeling the earthquake, with most of the reports coming from nearby Little Egg Harbor Township. 

The earthquake is the first one reported in New Jersey in more than six months. A 2.1 magnitude quake was reported in western New Jersey near Pennsylvania in December. 

Light shaking was felt, but there were no reports of injuries or damage.null

Associated Press contributed to this report.