The Next Major Quake: The Sixth Seal of NYC

        

New York is overdue an earthquake from faults under city

New York is OVERDUE an earthquake from a ‚brittle grid‘ of faults under the city, expert warns

• New York City last experienced a M5 or higher earthquake in 1884, experts say
• It’s thought that these earthquakes occur on a roughly 150-year periodicity 
• Based on this, some say the city could be overdue for the next major quake 

By Cheyenne Macdonald For Dailymail.com

Published: 15:50 EDT, 1 September 2017 | Updated: 12:00 EDT, 2 September 2017

When you think of the impending earthquake risk in the United States, it’s likely California or the Pacific Northwest comes to mind.

But, experts warn a system of faults making up a ‘brittle grid’ beneath New York City could also be loading up for a massive temblor.

The city has been hit by major quakes in the past, along what’s thought to be roughly 150-year intervals, and researchers investigating these faults now say the region could be overdue for the next event.

Experts warn a system of faults making up a ‘brittle grid’ beneath New York City could also be loading up for a massive temblor. The city has been hit by major quakes in the past, along what’s thought to be roughly 150-year intervals. A stock image is pictured

THE ‚CONEY ISLAND EARTHQUAKE‘

On August 10, 1884, New York was struck by a magnitude 5.5 earthquake with an epicentre located in Brooklyn.

While there was little damage and few injuries reported, anecdotal accounts of the event reveal the frightening effects of the quake.

One newspaper even reported that it caused someone to die from fright.

According to a New York Times report following the quake, massive buildings, including the Post Office swayed back and forth.

And, police said they felt the Brooklyn Bridge swaying ‘as if struck by a hurricane,’ according to an adaptation of Kathryn Miles’ book Quakeland: On the Road to America’s Next Devastating Earthquake.

The rumbles were felt across a 70,000-square-mile area, causing broken windows and cracked walls as far as Pennsylvania and Connecticut.

The city hasn’t experienced an earthquake this strong since.

According to geologist Dr Charles Merguerian, who has walked the entirety of Manhattan to assess its seismicity, there are a slew of faults running through New York, reports author Kathryn Miles in an adaptation of her new book Quakeland: On the Road to America’s Next Devastating Earthquake.

One such fault passes through 125th street, otherwise known as the Manhattanville Fault.

While there have been smaller quakes in New York’s recent past, including a magnitude 2.6 that struck in October 2001, it’s been decades since the last major tremor of M 5 or more.

And, most worryingly, the expert says there’s no way to predict exactly when a quake will strike.

‘That’s a question you really can’t answer,’ Merguerian has explained in the past.

‘All we can do is look at the record, and the record is that there was a relatively large earthquake here in the city in 1737, and in 1884, and that periodicity is about 150 year heat cycle.

‘So you have 1737, 1884, 20- and, we’re getting there. But statistics can lie.

‘An earthquake could happen any day, or it couldn’t happen for 100 years, and you just don’t know, there’s no way to predict.’

Compared the other parts of the United States, the risk of an earthquake in New York may not seem as pressing.

But, experts explain that a quake could happen anywhere.

According to geologist Dr Charles Merguerian, there are a slew of faults running through NY. One is the Ramapo Fault

‘All states have some potential for damaging earthquake shaking,’ according to the US Geological Survey.

‘Hazard is especially high along the west coast but also in the intermountain west, and in parts of the central and eastern US.’

A recent assessment by the USGS determined that the earthquake hazard along the East Coast may previously have been underestimated.

‘The eastern U.S. has the potential for larger and more damaging earthquakes than considered in previous maps and assessments,’ the USGS report explained.

The experts point to a recent example – the magnitude 5.8 earthquake that hit Virginia in 2011, which was among the largest to occur on the east coast in the last century.

This event suggests the area could be subjected to even larger earthquakes, even raising the risk for Charleston, SC.

It also indicates that New York City may be at higher risk than once thought.

A recent assessment by the USGS determined that the earthquake hazard along the East Coast may previously have been underestimated. The varying risks around the US can be seen above, with New York City in the mid-range (yellow).

The Next Major Quake: The Sixth Seal of NYC

         

New York is overdue an earthquake from faults under city

New York is OVERDUE an earthquake from a ‚brittle grid‘ of faults under the city, expert warns

• New York City last experienced a M5 or higher earthquake in 1884, experts say
• It’s thought that these earthquakes occur on a roughly 150-year periodicity 
• Based on this, some say the city could be overdue for the next major quake 

By Cheyenne Macdonald For Dailymail.com

Published: 15:50 EDT, 1 September 2017 | Updated: 12:00 EDT, 2 September 2017

When you think of the impending earthquake risk in the United States, it’s likely California or the Pacific Northwest comes to mind.

But, experts warn a system of faults making up a ‘brittle grid’ beneath New York City could also be loading up for a massive temblor.

The city has been hit by major quakes in the past, along what’s thought to be roughly 150-year intervals, and researchers investigating these faults now say the region could be overdue for the next event.

Experts warn a system of faults making up a ‘brittle grid’ beneath New York City could also be loading up for a massive temblor. The city has been hit by major quakes in the past, along what’s thought to be roughly 150-year intervals. A stock image is pictured

THE ‚CONEY ISLAND EARTHQUAKE‘

On August 10, 1884, New York was struck by a magnitude 5.5 earthquake with an epicentre located in Brooklyn.

While there was little damage and few injuries reported, anecdotal accounts of the event reveal the frightening effects of the quake.

One newspaper even reported that it caused someone to die from fright.

According to a New York Times report following the quake, massive buildings, including the Post Office swayed back and forth.

And, police said they felt the Brooklyn Bridge swaying ‘as if struck by a hurricane,’ according to an adaptation of Kathryn Miles’ book Quakeland: On the Road to America’s Next Devastating Earthquake.

The rumbles were felt across a 70,000-square-mile area, causing broken windows and cracked walls as far as Pennsylvania and Connecticut.

The city hasn’t experienced an earthquake this strong since.

According to geologist Dr Charles Merguerian, who has walked the entirety of Manhattan to assess its seismicity, there are a slew of faults running through New York, reports author Kathryn Miles in an adaptation of her new book Quakeland: On the Road to America’s Next Devastating Earthquake.

One such fault passes through 125th street, otherwise known as the Manhattanville Fault.

While there have been smaller quakes in New York’s recent past, including a magnitude 2.6 that struck in October 2001, it’s been decades since the last major tremor of M 5 or more.

And, most worryingly, the expert says there’s no way to predict exactly when a quake will strike.

‘That’s a question you really can’t answer,’ Merguerian has explained in the past.

‘All we can do is look at the record, and the record is that there was a relatively large earthquake here in the city in 1737, and in 1884, and that periodicity is about 150 year heat cycle.

‘So you have 1737, 1884, 20- and, we’re getting there. But statistics can lie.

‘An earthquake could happen any day, or it couldn’t happen for 100 years, and you just don’t know, there’s no way to predict.’

Compared the other parts of the United States, the risk of an earthquake in New York may not seem as pressing.

But, experts explain that a quake could happen anywhere.

According to geologist Dr Charles Merguerian, there are a slew of faults running through NY. One is the Ramapo Fault

‘All states have some potential for damaging earthquake shaking,’ according to the US Geological Survey.

‘Hazard is especially high along the west coast but also in the intermountain west, and in parts of the central and eastern US.’

A recent assessment by the USGS determined that the earthquake hazard along the East Coast may previously have been underestimated.

‘The eastern U.S. has the potential for larger and more damaging earthquakes than considered in previous maps and assessments,’ the USGS report explained.

The experts point to a recent example – the magnitude 5.8 earthquake that hit Virginia in 2011, which was among the largest to occur on the east coast in the last century.

This event suggests the area could be subjected to even larger earthquakes, even raising the risk for Charleston, SC.

It also indicates that New York City may be at higher risk than once thought.

A recent assessment by the USGS determined that the earthquake hazard along the East Coast may previously have been underestimated. The varying risks around the US can be seen above, with New York City in the mid-range (yellow).

The Sixth Seal Long Overdue (Revelation 6)

       

ON THE MAP; Exploring the Fault Where the Next Big One May Be Waiting

The Big One Awaits

By MARGO NASH

Published: March 25, 2001

Alexander Gates, a geology professor at Rutgers-Newark, is co-author of “The Encyclopedia of Earthquakes and Volcanoes,“ which will be published by Facts on File in July. He has been leading a four-year effort to remap an area known as the Sloatsburg Quadrangle, a 5-by-7-mile tract near Mahwah that crosses into New York State. The Ramapo Fault, which runs through it, was responsible for a big earthquake in 1884, and Dr. Gates warns that a recurrence is overdue. He recently talked about his findings.

Q. What have you found?

A. We’re basically looking at a lot more rock, and we’re looking at the fracturing and jointing in the bedrock and putting it on the maps. Any break in the rock is a fracture. If it has movement, then it’s a fault. There are a lot of faults that are offshoots of the Ramapo. Basically when there are faults, it means you had an earthquake that made it. So there was a lot of earthquake activity to produce these features. We are basically not in a period of earthquake activity along the Ramapo Fault now, but we can see that about six or seven times in history, about 250 million years ago, it had major earthquake activity. And because it’s such a fundamental zone of weakness, anytime anything happens, the Ramapo Fault goes.

Q. Where is the Ramapo Fault?

 A. The fault line is in western New Jersey and goes through a good chunk of the state, all the way down to Flemington. It goes right along where they put in the new 287. It continues northeast across the Hudson River right under the Indian Point power plant up into Westchester County. There are a lot of earthquakes rumbling around it every year, but not a big one for a while.

Q. Did you find anything that surprised you?

A. I found a lot of faults, splays that offshoot from the Ramapo that go 5 to 10 miles away from the fault. I have looked at the Ramapo Fault in other places too. I have seen splays 5 to 10 miles up into the Hudson Highlands. And you can see them right along the roadsides on 287. There’s been a lot of damage to those rocks, and obviously it was produced by fault activities. All of these faults have earthquake potential.

Q. Describe the 1884 earthquake.

A. It was in the northern part of the state near the Sloatsburg area. They didn’t have precise ways of describing the location then. There was lots of damage. Chimneys toppled over. But in 1884, it was a farming community, and there were not many people to be injured. Nobody appears to have written an account of the numbers who were injured.

Q. What lessons we can learn from previous earthquakes?

A. In 1960, the city of Agadir in Morocco had a 6.2 earthquake that killed 12,000 people, a third of the population, and injured a third more. I think it was because the city was unprepared.There had been an earthquake in the area 200 years before. But people discounted the possibility of a recurrence. Here in New Jersey, we should not make the same mistake. We should not forget that we had a 5.4 earthquake 117 years ago. The recurrence interval for an earthquake of that magnitude is every 50 years, and we are overdue. The Agadir was a 6.2, and a 5.4 to a 6.2 isn’t that big a jump.

Q. What are the dangers of a quake that size?

A. When you’re in a flat area in a wooden house it’s obviously not as dangerous, although it could cut off a gas line that could explode. There’s a real problem with infrastructure that is crumbling, like the bridges with crumbling cement. There’s a real danger we could wind up with our water supplies and electricity cut off if a sizable earthquake goes off. The best thing is to have regular upkeep and keep up new building codes. The new buildings will be O.K. But there is a sense of complacency.

MARGO NASH

New York Subways at the Sixth Seal (Revelation 6)

                      How vulnerable are NYC’s underwater subway tunnels to flooding?

Ashley Fetters
New York City is full of peculiar phenomena—rickety fire escapes; 100-year-old subway tunnels; air conditioners propped perilously into window frames—that can strike fear into the heart of even the toughest city denizen. But should they? Every month, writer Ashley Fetters will be exploring—and debunking—these New York-specific fears, letting you know what you should actually worry about, and what anxieties you can simply let slip away.
The 25-minute subway commute from Crown Heights to the Financial District on the 2/3 line is, in my experience, a surprisingly peaceful start to the workday—save for one 3,100-foot stretch between the Clark Street and Wall Street stations, where for three minutes I sit wondering what the probability is that I will soon die a torturous, claustrophobic drowning death right here in this subway car.
The Clark Street Tunnel, opened in 1916, is one of approximately a dozen tunnels that escort MTA passengers from one borough to the next underwater—and just about all of them, with the exception of the 1989 addition of the 63rd Street F train tunnel, were constructed between 1900 and 1936.
Each day, thousands of New Yorkers venture across the East River and back again through these tubes buried deep in the riverbed, some of which are nearing or even past their 100th birthdays. Are they wrong to ponder their own mortality while picturing one of these watery catacombs suddenly springing a leak?
Mostly yes, they are, says Michael Horodniceanu, the former president of MTA Capital Construction and current principal of Urban Advisory Group. First, it’s important to remember that the subway tunnel is built under the riverbed, not just in the river—so what immediately surrounds the tunnel isn’t water but some 25 feet of soil. “There’s a lot of dirt on top of it,” Horodniceanu says. “It’s well into the bed of the bottom of the channel.”
And second, as Angus Kress Gillespie, author of Crossing Under the Hudson: The Story of the Holland and Lincoln Tunnels, points out, New York’s underwater subway tunnels are designed to withstand some leaking. And withstand it they do: Pumps placed below the floor of the tunnel, he says, are always running, always diverting water seepage into the sewers. (Horodniceanu says the amount of water these pumps divert into the sewer system each day numbers in the thousands of gallons.)
Additionally, MTA crews routinely repair the grouting and caulking, and often inject a substance into the walls that creates a waterproof membrane outside the tunnel—which keeps water out of the tunnel and relieves any water pressure acting on its walls. New tunnels, Horodniceanu points out, are even built with an outside waterproofing membrane that works like an umbrella: Water goes around it, it falls to the sides, and then it gets channeled into a pumping station and pumped out.
Of course, the classic New York nightmare scenario isn’t just a cute little trickle finding its way in. The anxiety daydream usually involves something sinister, or seismic. The good news, however, is that while an earthquake or explosion would indeed be bad for many reasons, it likely wouldn’t result in the frantic flooding horror scene that plays out in some commuters’ imaginations.
The Montague Tube, which sustained severe damage during Hurricane Sandy.
MTA New York City Transit / Marc A. Hermann
Horodniceanu assures me that tunnels built more recently are “built to withstand a seismic event.” The older tunnels, however—like, um, the Clark Street Tunnel—“were not seismically retrofitted, let me put it that way,” Horodniceanu says. “But the way they were built is in such a way that I do not believe an earthquake would affect them.” They aren’t deep enough in the ground, anyway, he says, to be too intensely affected by a seismic event. (The MTA did not respond to a request for comment.)
One of the only real threats to tunnel infrastructure, Horodniceanu adds, is extreme weather. Hurricane Sandy, for example, caused flooding in the tunnels, which “created problems with the infrastructure.” He continues, “The tunnels have to be rebuilt as a result of saltwater corroding the infrastructure.”
Still, he points out, hurricanes don’t exactly happen with no warning. So while Hurricane Sandy did cause major trauma to the tunnels, train traffic could be stopped with ample time to keep passengers out of harm’s way. In 2012, Governor Andrew Cuomo directed all the MTA’s mass transit services to shut down at 7 p.m. the night before Hurricane Sandy was expected to hit New York City.
And Gillespie, for his part, doubts even an explosion would result in sudden, dangerous flooding. A subway tunnel is not a closed system, he points out; it’s like a pipe that’s open at both ends. “The force of a blast would go forwards and backwards out the exit,” he says.
So the subway-train version of that terrifying Holland Tunnel flood scene in Sylvester Stallone’s Daylight is … unrealistic, right?
“Yeah,” Gillespie laughs. “Yeah. It is.”
Got a weird New York anxiety that you want explored? E-mail tips@curbed.com, and we may include it in a future column.

Economic Consequences of the Sixth Seal (Revelation 6:12)

   

Scenario Earthquakes for Urban Areas Along the Atlantic Seaboard of the United States

NYCEM.org

If today a magnitude 6 earthquake were to occur centered on New York City, what would its effects be? Will the loss be 10 or 100 billion dollars? Will there be 10 or 10,000 fatalities? Will there be 1,000 or 100,000 homeless needing shelter? Can government function, provide assistance, and maintain order?
At this time, no satisfactory answers to these questions are available. A few years ago, rudimentary scenario studies were made for Boston and New York with limited scope and uncertain results. For most eastern cities, including Washington D.C., we know even less about the economic, societal and political impacts from significant earthquakes, whatever their rate of occurrence.
Why do we know so little about such vital public issues? Because the public has been lulled into believing that seriously damaging quakes are so unlikely in the east that in essence we do not need to consider them. We shall examine the validity of this widely held opinion.
Is the public’s earthquake awareness (or lack thereof) controlled by perceived low Seismicity, Seismic Hazard, or Seismic Risk? How do these three seismic features differ from, and relate to each other? In many portions of California, earthquake awareness is refreshed in a major way about once every decade (and in some places even more often) by virtually every person experiencing a damaging event. The occurrence of earthquakes of given magnitudes in time and space, not withstanding their effects, are the manifestations of seismicity. Ground shaking, faulting, landslides or soil liquefaction are the manifestations of seismic hazard. Damage to structures, and loss of life, limb, material assets, business and services are the manifestations of seismic risk. By sheer experience, California’s public understands fairly well these three interconnected manifestations of the earthquake phenomenon. This awareness is reflected in public policy, enforcement of seismic regulations, and preparedness in both the public and private sector. In the eastern U.S., the public and its decision makers generally do not understand them because of inexperience. Judging seismic risk by rates of seismicity alone (which are low in the east but high in the west) has undoubtedly contributed to the public’s tendency to belittle the seismic loss potential for eastern urban regions.
Let us compare two hypothetical locations, one in California and one in New York City. Assume the location in California does experience, on average, one M = 6 every 10 years, compared to New York once every 1,000 years. This implies a ratio of rates of seismicity of 100:1. Does that mean the ratio of expected losses (when annualized per year) is also 100:1? Most likely not. That ratio may be closer to 10:1, which seems to imply that taking our clues from seismicity alone may lead to an underestimation of the potential seismic risks in the east. Why should this be so?
To check the assertion, let us make a back-of-the-envelope estimate. The expected seismic risk for a given area is defined as the area-integrated product of: seismic hazard (expected shaking level), assets ($ and people), and the assets’ vulnerabilities (that is, their expected fractional loss given a certain hazard – say, shaking level). Thus, if we have a 100 times lower seismicity rate in New York compared to California, which at any given point from a given quake may yield a 2 times higher shaking level in New York compared to California because ground motions in the east are known to differ from those in the west; and if we have a 2 times higher asset density (a modest assumption for Manhattan!), and a 2 times higher vulnerability (again a modest assumption when considering the large stock of unreinforced masonry buildings and aged infrastructure in New York), then our California/New York ratio for annualized loss potential may be on the order of (100/(2x2x2)):1. That implies about a 12:1 risk ratio between the California and New York location, compared to a 100:1 ratio in seismicity rates.
From this example it appears that seismic awareness in the east may be more controlled by the rate of seismicity than by the less well understood risk potential. This misunderstanding is one of the reasons why earthquake awareness and preparedness in the densely populated east is so disproportionally low relative to its seismic loss potential. Rare but potentially catastrophic losses in the east compete in attention with more frequent moderate losses in the west. New York City is the paramount example of a low-probability, high-impact seismic risk, the sort of risk that is hard to insure against, or mobilize public action to reduce the risks.
There are basically two ways to respond. One is to do little and wait until one or more disastrous events occur. Then react to these – albeit disastrous – “windows of opportunity.” That is, pay after the unmitigated facts, rather than attempt to control their outcome. This is a high-stakes approach, considering the evolved state of the economy. The other approach is to invest in mitigation ahead of time, and use scientific knowledge and inference, education, technology transfer, and combine it with a mixture of regulatory and/or economic incentives to implement earthquake preparedness. The National Earthquake Hazard Reduction Program (NEHRP) has attempted the latter while much of the public tends to cling to the former of the two options. Realistic and reliable quantitative loss estimation techniques are essential to evaluate the relative merits of the two approaches.
This paper tries to bring into focus some of the seismological factors which are but one set of variables one needs for quantifying the earthquake loss potential in eastern U.S. urban regions. We use local and global analogs for illustrating possible scenario events in terms of risk. We also highlight some of the few local steps that have been undertaken towards mitigating against the eastern earthquake threat; and discuss priorities for future actions.

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 km2from 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.