History Says Expect The Sixth Seal In New York (Revelation 6:12)

              

History Says New York Is Earthquake Prone

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If the past is any indication, New York can be hit by an earthquake, claims John Armbruster, a seismologist at Columbia University’s Lamont-Doherty Earth Observatory.

Based on historical precedent, Armbruster says the New York City metro area is susceptible to an earthquake of at least a magnitude of 5.0 once a century.

According to the New York Daily News, Lynn Skyes, lead author of a recent study by seismologists at the Lamont-Doherty Earth Observatory adds that a magnitude-6 quake hits the area about every 670 years, and magnitude-7 every 3,400 years.

A 5.2-magnitude quake shook New York City in 1737 and another of the same severity hit in 1884.

Tremors were felt from Maine to Virginia.

There are several fault lines in the metro area, including one along Manhattan’s 125th St. – which may have generated two small tremors in 1981 and may have been the source of the major 1737 earthquake, says Armbruster.

There’s another fault line on Dyckman St. and one in Dobbs Ferry in nearby Westchester County.

“The problem here comes from many subtle faults,” explained Skyes after the study was published.

He adds: “We now see there is earthquake activity on them. Each one is small, but when you add them up, they are probably more dangerous than we thought.”

“Considering population density and the condition of the region’s infrastructure and building stock, it is clear that even a moderate earthquake would have considerable consequences in terms of public safety and economic impact,” says the New York City Area Consortium for Earthquake Loss Mitigation on its website.

Armbruster says a 5.0-magnitude earthquake today likely would result in casualties and hundreds of millions of dollars in damage.

“I would expect some people to be killed,” he notes.

The scope and scale of damage would multiply exponentially with each additional tick on the Richter scale. (ANI)

Revelation 6:12 — The Sixth Seal In NYC Is About to Break

New York City is Past Due for an Earthquake
by Jessica Dailey, 03/22/11
filed under: News
New York City may appear to be an unlikely place for a major earthquake, but according to history, we’re past due for a serious shake. Seismologists at Columbia University’s Lamont-Doherty Earth Observatory say that about once every 100 years, an earthquake of at least a magnitude of 5.0 rocks the Big Apple. The last one was a 5.3 tremor that hit in 1884 — no one was killed, but buildings were damaged.
Any tremor above a 6.0 magnitude can be catastrophic, but it is extremely unlikely that New York would ever experience a quake like the recent 8.9 earthquake in Japan. A study by the Earth Observatory found that a 6.0 quake hits the area about every 670 years, and a 7.0 magnitude hits about every 3,400 years.
There are several fault lines in New York’s metro area, including one along 125th Street, which may have caused two small tremors in 1981 and a 5.2 magnitude quake in 1737. There is also a fault line on Dyckman Street in Inwood, and another in Dobbs Ferry in Westchester County. The New York City Area Consortium for Earthquake Loss Mitigation rates the chance of an earthquake hitting the city as moderate.
John Armbruster, a seismologist at the Earth Observatory, said that if a 5.0 magnitude quake struck New York today, it would result in hundreds of millions, possibly billions of dollars in damages. The city’s skyscrapers would not collapse, but older brick buildings and chimneys would topple, likely resulting in casualities.
The Earth Observatory is expanding its studies of potential earthquake damage to the city. They currently have six seismometers at different landmarks throughout the five boroughs, and this summer, they plan to place one at the arch in Washington Square Park and another in Bryant Park.
Won-Young Kim, who works alongside Armbuster, says his biggest concern is that we can’t predict when an earthquake might hit. “It can happen anytime soon,” Kim told the Metro. If it happened tomorrow, he added, “I would not be surprised. We can expect it any minute, we just don’t know when and where.”
Armbuster voiced similar concerns to the Daily News. “Will there be one in my lifetime or your lifetime? I don’t know,” he said. “But this is the longest period we’ve gone without one.”
Via Metro and NY Daily News
Images © Ed Yourdon

Earthquake activity in the New York City area: Revelation 6

          

Earthquake activity in the New York City area

Wikipedia

Although the eastern United States is not as seismically active as regions near plate boundaries, large and damaging earthquakes do occur there. Furthermore, when these rare eastern U.S. earthquakes occur, the areas affected by them are much larger than for western U.S. earthquakes of the same magnitude. Thus, earthquakes represent at least a moderate hazard to East Coast cities, including New York City and adjacent areas of very high population density.

Seismicity in the vicinity of New York City. Data are from the U.S. Geological Survey (Top, USGS) and the National Earthquake Information Center (Bottom, NEIC). In the top figure, closed red circles indicate 1924-2006 epicenters and open black circles indicate locations of the larger earthquakes that occurred in 1737, 1783 and 1884. Green lines indicate the trace of the Ramapo fault.

As can be seen in the maps of earthquake activity in this region(shown in the figure), seismicity is scattered throughout most of the New York City area, with some hint of a concentration of earthquakes in the area surrounding Manhattan Island. The largest known earthquake in this region occurred in 1884 and had a magnitude of approximately 5.For this earthquake, observations of fallen bricks and cracked plaster were reported from eastern Pennsylvania to central Connecticut, and the maximum intensity reported was at two sites in western Long Island (Jamaica, New York and Amityville, New York). Two other earthquakes of approximately magnitude 5 occurred in this region in 1737 and 1783. The figure on the right shows maps of the distribution of earthquakes of magnitude 3 and greater that occurred in this region from 1924 to 2010, along with locations of the larger earthquakes that occurred in 1737, 1783 and 1884.

Background

The NYC area is part of the geologically complex structure of the Northern Appalachian Mountains. This complex structure was formed during the past half billion years when the Earth’s crust underlying the Northern Appalachians was the site of two major geological episodes, each of which has left its imprint on the NYC area bedrock. Between about 450 million years ago and about 250 million years ago, the Northern Appalachian region was affected by a continental collision, in which the ancient African continent collided with the ancient North American continent to form the supercontinent Pangaea. Beginning about 200 million years ago, the present-day Atlantic ocean began to form as plate tectonic forces began to rift apart the continent of Pangaea. The last major episode of geological activity to affect the bedrock in the New York area occurred about 100 million years ago, during the Mesozoic era, when continental rifting that led to the opening of the present-day Atlantic ocean formed the Hartford and Newark Mesozoic rift basins.

Earthquake rates in the northeastern United States are about 50 to 200 times lower than in California, but the earthquakes that do occur in the northeastern U.S. are typically felt over a much broader region than earthquakes of the same magnitude in the western U.S.This means the area of damage from an earthquake in the northeastern U.S. could be larger than the area of damage caused by an earthquake of the same magnitude in the western U.S. The cooler rocks in the northeastern U.S. contribute to the seismic energy propagating as much as ten times further than in the warmer rocks of California. A magnitude 4.0 eastern U.S. earthquake typically can be felt as far as 100 km (60 mi) from its epicenter, but it infrequently causes damage near its source. A magnitude 5.5 eastern U.S. earthquake, although uncommon, can be felt as far as 500 km (300 mi) from its epicenter, and can cause damage as far away as 40 km (25 mi) from its epicenter. Earthquakes stronger than about magnitude 5.0 generate ground motions that are strong enough to be damaging in the epicentral area.

At well-studied plate boundaries like the San Andreas fault system in California, scientists can often make observations that allow them to identify the specific fault on which an earthquake took place. In contrast, east of the Rocky Mountains this is rarely the case.  The NYC area is far from the boundaries of the North American plate, which are in the center of the Atlantic Ocean, in the Caribbean Sea, and along the west coast of North America. The seismicity of the northeastern U.S. is generally considered to be due to ancient zones of weakness that are being reactivated in the present-day stress field. In this model, pre-existing faults that were formed during ancient geological episodes persist in the intraplate crust, and the earthquakes occur when the present-day stress is released along these zones of weakness. The stress that causes the earthquakes is generally considered to be derived from present-day rifting at the Mid-Atlantic ridge.

Earthquakes and geologically mapped faults in the Northeastern U.S.

The northeastern U.S. has many known faults, but virtually all of the known faults have not been active for perhaps 90 million years or more. Also, the locations of the known faults are not well determined at earthquake depths. Accordingly, few (if any) earthquakes in the region can be unambiguously linked to known faults. Given the current geological and seismological data, it is difficult to determine if a known fault in this region is still active today and could produce a modern earthquake. As in most other areas east of the Rocky Mountains, the best guide to earthquake hazard in the northeastern U.S. is probably the locations of the past earthquakes themselves.

The Ramapo fault and other New York City area faults

The Ramapo Fault, which marks the western boundary of the Newark rift basin, has been argued to be a major seismically active feature of this region,but it is difficult to discern the extent to which the Ramapo fault (or any other specific mapped fault in the area) might be any more of a source of future earthquakes than any other parts of the region. The Ramapo Fault zone spans more than 185 miles (300 kilometers) in New York, New Jersey, and Pennsylvania. It is a system of faults between the northern Appalachian Mountains and Piedmont areas to the east. This fault is perhaps the best known fault zone in the Mid-Atlantic region, and some small earthquakes have been known to occur in its vicinity. Recently, public knowledge about the fault has increased – especially after the 1970s, when the fault’s proximity to the Indian Point nuclear plant in New York was noticed.

There is insufficient evidence to unequivocally demonstrate any strong correlation of earthquakes in the New York City area with specific faults or other geologic structures in this region. The damaging earthquake affecting New York City in 1884 was probably not associated with the Ramapo fault because the strongest shaking from that earthquake occurred on Long Island (quite far from the trace of the Ramapo fault). The relationship between faults and earthquakes in the New York City area is currently understood to be more complex than any simple association of a specific earthquake with a specific mapped fault.

A 2008 study argued that a magnitude 6 or 7 earthquake might originate from the Ramapo fault zone, which would almost definitely spawn hundreds or even thousands of fatalities and billions of dollars in damage. Studying around 400 earthquakes over the past 300 years, the study also argued that there was an additional fault zone extending from the Ramapo Fault zone into southwestern Connecticut. As can be seen in the above figure of seismicity, earthquakes are scattered throughout this region, with no particular concentration of activity along the Ramapo fault, or along the hypothesized fault zone extending into southwestern Connecticut.

Just off the northern terminus of the Ramapo fault is the Indian Point Nuclear Power Plant, built between 1956 and 1960 by Consolidated Edison Company. The plant began operating in 1963, and it has been the subject of a controversy over concerns that an earthquake from the Ramapo fault will affect the power plant. Whether or not the Ramapo fault actually does pose a threat to this nuclear power plant remains an open question.

Economic Consequences of the Sixth Seal in NYC (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.

East Coast & NYC Still Unprepared For The Sixth Seal (Revelation 6:12)

    

East Coast Earthquake Preparedness
By By BEN NUCKOLS
Posted: 08/25/2011 8:43 am EDT
WASHINGTON — There were cracks in the Washington Monument and broken capstones at the National Cathedral. In the District of Columbia suburbs, some people stayed in shelters because of structural concerns at their apartment buildings.
A day after the East Coast’s strongest earthquake in 67 years, inspectors assessed the damage and found that most problems were minor. But the shaking raised questions about whether this part of the country, with its older architecture and inexperience with seismic activity, is prepared for a truly powerful quake.
The 5.8 magnitude quake felt from Georgia north to Canada prompted swift inspections of many structures Wednesday, including bridges and nuclear plants. An accurate damage estimate could take weeks, if not longer. And many people will not be covered by insurance.
In a small Virginia city near the epicenter, the entire downtown business district was closed. School was canceled for two weeks to give engineers time to check out cracks in several buildings.
At the 555-foot Washington Monument, inspectors found several cracks in the pyramidion – the section at the top of the obelisk where it begins narrowing to a point.
A 4-foot crack was discovered Tuesday during a visual inspection by helicopter. It cannot be seen from the ground. Late Wednesday, the National Park Service announced that structural engineers had found several additional cracks inside the top of the monument.
Carol Johnson, a park service spokeswoman, could not say how many cracks were found but said three or four of them were “significant.” Two structural engineering firms that specialize in assessing earthquake damage were being brought in to conduct a more thorough inspection on Thursday.
The monument, by far the tallest structure in the nation’s capital, was to remain closed indefinitely, and Johnson said the additional cracks mean repairs are likely to take longer. It has never been damaged by a natural disaster, including earthquakes in Virginia in 1897 and New York in 1944.
Tourists arrived at the monument Wednesday morning only to find out they couldn’t get near it. A temporary fence was erected in a wide circle about 120 feet from the flags that surround its base. Walkways were blocked by metal barriers manned by security guards.
“Is it really closed?” a man asked the clerk at the site’s bookstore.
“It’s really closed,” said the clerk, Erin Nolan. Advance tickets were available for purchase, but she cautioned against buying them because it’s not clear when the monument will open.
“This is pretty much all I’m going to be doing today,” Nolan said.
Tuesday’s quake was centered about 40 miles northwest of Richmond, 90 miles south of Washington and 3.7 miles underground. In the nearby town of Mineral, Va., Michael Leman knew his Main Street Plumbing & Electrical Supply business would need – at best – serious and expensive repairs.
At worst, it could be condemned. The facade had become detached from the rest of the building, and daylight was visible through a 4- to 6-inch gap that opened between the front wall and ceiling.
“We’re definitely going to open back up,” Leman said. “I’ve got people’s jobs to look out for.”
Leman said he is insured, but some property owners might not be so lucky.
The Insurance Information Institute said earthquakes are not covered under standard U.S. homeowners or business insurance policies, although supplemental coverage is usually available.
The institute says coverage for other damage that may result from earthquakes, such as fire and water damage from burst gas or water pipes, is provided by standard homeowners and business insurance policies in most states. Cars and other vehicles with comprehensive insurance would also be protected.
The U.S. Geological Survey classified the quake as Alert Level Orange, the second-most serious category on its four-level scale. Earthquakes in that range lead to estimated losses between $100 million and $1 billion.
In Culpeper, Va., about 35 miles from the epicenter, walls had buckled at the old sanctuary at St. Stephen’s Episcopal Church, which was constructed in 1821 and drew worshippers including Confederate Gens. Robert E. Lee and J.E.B. Stuart. Heavy stone ornaments atop a pillar at the gate were shaken to the ground. A chimney from the old Culpeper Baptist Church built in 1894 also tumbled down.
At the Washington National Cathedral, spokesman Richard Weinberg said the building’s overall structure remains sound and damage was limited to “decorative elements.”
Massive stones atop three of the four spires on the building’s central tower broke off, crashing onto the roof. At least one of the spires is teetering badly, and cracks have appeared in some flying buttresses.
Repairs were expected to cost millions of dollars – an expense not covered by insurance.
“Every single portion of the exterior is carved by hand, so everything broken off is a piece of art,” Weinberg said. “It’s not just the labor, but the artistry of replicating what was once there.”
The building will remain closed as a precaution. Services to dedicate the memorial honoring Rev. Martin Luther King Jr. were moved.
Other major cities along the East Coast that felt the shaking tried to gauge the risk from another quake.
A few hours after briefly evacuating New York City Hall, Mayor Michael Bloomberg said the city’s newer buildings could withstand a more serious earthquake. But, he added, questions remain about the older buildings that are common in a metropolis founded hundreds of years ago.
“We think that the design standards of today are sufficient against any eventuality,” he said. But “there are questions always about some very old buildings. … Fortunately those tend to be low buildings, so there’s not great danger.”
An earthquake similar to the one in Virginia could do billions of dollars of damage if it were centered in New York, said Barbara Nadel, an architect who specializes in securing buildings against natural disasters and terrorism.
The city’s 49-page seismic code requires builders to prepare for significant shifting of the earth. High-rises must be built with certain kinds of bracing, and they must be able to safely sway at least somewhat to accommodate for wind and even shaking from the ground, Nadel said.
Buildings constructed in Boston in recent decades had to follow stringent codes comparable to anything in California, said Vernon Woodworth, an architect and faculty member at the Boston Architectural College. New construction on older structures also must meet tough standards to withstand severe tremors, he said.
It’s a different story with the city’s older buildings. The 18th- and 19th-century structures in Boston’s Back Bay, for instance, were often built on fill, which can liquefy in a strong quake, Woodworth said. Still, there just aren’t many strong quakes in New England.
The last time the Boston area saw a quake as powerful as the one that hit Virginia on Tuesday was in 1755, off Cape Ann, to the north. A repeat of that quake would likely cause deaths, Woodworth said. Still, the quakes are so infrequent that it’s difficult to weigh the risks versus the costs of enacting tougher building standards regionally, he said.
People in several of the affected states won’t have much time to reflect before confronting another potential emergency. Hurricane Irene is approaching the East Coast and could skirt the Mid-Atlantic region by the weekend and make landfall in New England after that.
In North Carolina, officials were inspecting an aging bridge that is a vital evacuation route for people escaping the coastal barrier islands as the storm approaches.
Speaking at an earthquake briefing Wednesday, Washington Mayor Vincent Gray inadvertently mixed up his disasters.
“Everyone knows, obviously, that we had a hurricane,” he said before realizing his mistake.
“Hurricane,” he repeated sheepishly as reporters and staffers burst into laughter. “I’m getting ahead of myself!”
___
Associated Press writers Sam Hananel in Washington; Alex Dominguez in Baltimore; Bob Lewis in Mineral, Va.; Samantha Gross in New York City; and Jay Lindsay in Boston contributed to this report.

History Says Expect The Sixth Seal In New York (Revelation 6:12)

History Says New York Is Earthquake Prone
If the past is any indication, New York can be hit by an earthquake, claims John Armbruster, a seismologist at Columbia University’s Lamont-Doherty Earth Observatory.
Based on historical precedent, Armbruster says the New York City metro area is susceptible to an earthquake of at least a magnitude of 5.0 once a century.
According to the New York Daily News, Lynn Skyes, lead author of a recent study by seismologists at the Lamont-Doherty Earth Observatory adds that a magnitude-6 quake hits the area about every 670 years, and magnitude-7 every 3,400 years.
A 5.2-magnitude quake shook New York City in 1737 and another of the same severity hit in 1884.
Tremors were felt from Maine to Virginia.
There are several fault lines in the metro area, including one along Manhattan’s 125th St. – which may have generated two small tremors in 1981 and may have been the source of the major 1737 earthquake, says Armbruster.
There’s another fault line on Dyckman St. and one in Dobbs Ferry in nearby Westchester County.
“The problem here comes from many subtle faults,” explained Skyes after the study was published.
He adds: “We now see there is earthquake activity on them. Each one is small, but when you add them up, they are probably more dangerous than we thought.”
“Considering population density and the condition of the region’s infrastructure and building stock, it is clear that even a moderate earthquake would have considerable consequences in terms of public safety and economic impact,” says the New York City Area Consortium for Earthquake Loss Mitigation on its website.
Armbruster says a 5.0-magnitude earthquake today likely would result in casualties and hundreds of millions of dollars in damage.
“I would expect some people to be killed,” he notes.
The scope and scale of damage would multiply exponentially with each additional tick on the Richter scale. (ANI)

A Closer Look At the Sixth Seal in NYC (Revelation 6:12)

A LOOK AT NEW YORK CITY’S EARTHQUAKE RISKS

By Spectrum News NY1 | April 2, 2018 @4:32 PM

Not every New Yorker felt when the ground shook on August 23, 2011.

When a magnitude 5.8 earthquake cracked the soil near Mineral, Virginia that day, the energy traveled through the Northeast.

Some New Yorkers watched their homes tremor, while others felt nothing.

Researchers say New York City is due for a significant earthquake originating near the five boroughs, based on previous smaller earthquakes in and around the city. While New York is at moderate risk for earthquakes, its high population and infrastructure could lead to significant damage when a magnitude 5 quake or stronger hits the area.

Unbeknownst to many, there are numerous fault lines in the city, but a few stand out for their size and prominence: the 125th Street Fault, the Dyckman Street Fault, the Mosholu Parkway Fault, and the East River Fault.

The 125th Street Fault is the largest, running along the street, extending from New Jersey to the East River. Part of it runs to the northern tip of Central Park, while a portion extends into Roosevelt Island.

The Dyckman Street Fault is located in Inwood, crossing the Harlem River and into Morris Heights, while the Mosholu Parkway Fault is north of the Dyckman Street and 125th Street Faults.

The East River Fault looks a bit like an obtuse angle, with its top portion running parallel, to the west of Central Park, before taking a horizontal turn near 32nd St. and extending into the East River and stopping short of Brooklyn.

Just outside of the city is the Dobbs Ferry Fault, located in suburban Westchester; and the Ramapo Fault, running from eastern Pennsylvania to the mid-Hudson Valley, passing within a few miles northwest of the Indian Point Nuclear Plant, less than 40 miles north of the city and astride the intersection of two active seismic zones.

The locations of faults and the prevalence of earthquakes is generally not a concern for most New Yorkers. One reason might be that perceptions of weaker earthquakes vary widely.

On Nov. 30, a magnitude 4.1 earthquake, centered near Dover, Delaware, could be felt in nearby states. Less than 200 miles away in New York City, some people reported on social media that they felt their houses and apartments shaking. At the same time, some New Yorkers, again, did not feel anything:

Won-Young Kim is a senior research scientist at Columbia University’s Lamont-Doherty Earth Observatory, which monitors and records data on earthquakes that occur in the northeast. Kim says it’s not clear who feels smaller earthquakes, as evident by a magnitude 0.8 quake in the city in December of 2004.

„Hundreds of people called local police, and police called us. Our system was unable to detect that tiny earthquake automatically,“ Kim said. „We looked at it, and, indeed, there was a small signal.“

Kim says some parts of the city will feel magnitude 1 or 2 earthquakes even if the seismic activity does not result in any damage.

You have to go back to before the 20th Century, however, to find the last significant earthquake that hit the city. According to Lamont-Doherty researchers, magnitude 5.2 earthquakes occurred in 1737 and 1884. In newspaper accounts, New Yorkers described chimneys falling down and feeling the ground shake underneath them.

„1737 — that was located close to Manhattan,“ Kim said. „It was very close to New York City.“

According to Kim, the 1884 quake was felt in areas in or close to the city, such as the Rockaways and Sandy Hook, New Jersey. But it was felt even as far away as Virginia and Maine.

From 1677 to 2007, there were 383 known earthquakes in a 15,000-square-mile area around New York City, researchers at Lamont-Doherty said in a 2008 study.

A 4.9 located in North Central New Jersey was felt in the city in 1783; a 4 hit Ardsley in 1985; and in 2001, magnitude 2.4 and 2.6 quakes were detected in Manhattan itself for the first time.

But the 1737 and 1884 quakes remain the only known ones of at least magnitude 5 to hit the city.

Smaller earthquakes are not to be ignored. Lamont-Doherty researchers say frequent small quakes occur in predictable ratios to larger ones and thus can be used — along with the fault lengths, detected tremors and calculations of how stress builds in the crust — to create a rough time scale.

The takeaway? New York City is due for a significant earthquake.

Researchers say New York City is susceptible to at least a magnitude 5 earthquake once every 100 years, a 6 about every 670 years, and 7 about every 3,400 years.

It’s been 134 years since New York was last hit by at least a magnitude 5. When it happens next, researchers say it won’t be much like 1884.

The city’s earthquake hazard is moderate, according to the New York City Area Consortium for Earthquake Loss Mitigation (NYCEM), but experts agree that, due to its higher population and infrastructure, the damage would be significant.

Before 1995, earthquake risks were not taken into consideration for the city’s building code. Thus, Lamont-Doherty says many older buildings, such as unenforced three- to six-story buildings, could suffer major damage or crumble.

The damage an earthquake causes is also dependent on what’s in the ground. According to the U.S. Geological Survey, bedrock is more resistant to earthquakes than sediment.

The upper third of Manhattan has harder soil that is more resistant to shaking. Parts of Midtown are more susceptible, while Downtown Manhattan’s soil is even softer, according to the NYCEM.

Exceptions to Upper Manhattan’s strength? Portions of Harlem and Inwood — both areas consist of a large amount of soft soil. Central Park has the strongest soil in Manhattan, outside of a small segment of Inwood..

Not all boroughs are created equal. While the Bronx is also made of solid bedrock, the ground in Queens and Brooklyn is softer.

„If you go to Queens and Brooklyn, you have sediment, so there would be more shaking relative to Manhattan,“ Kim said. „So, it’s not easy to say the damage would be the same.“

Analysis pins the damage from a magnitude 5 earthquake hitting New York City in the billions, according to Lamont-Doherty.

New York City is not a hotbed for seismic activity; it is not close to a tectonic plate, and it is not clear if one of the faults would be the source of a strong quake. But the predicted damage to the city has concerned many experts.

Until that day, earthquakes are isolated events for New Yorkers. Some have felt the ground move, while others have only felt shaking when subway cars travel underground.

But researchers agree: One day, the ground will wake up in the city that never sleeps, and all New Yorkers will understand what Mineral, Virginia felt when their homes rattled with the earth.