Sixth Seal: New York City (Revelation 6:12)

EARTHQUAKE HAZARD (Source: US Geological Survey)

NY hazard

New York State Geological Survey

Damaging earthquakes have occurred in New York and surely will again. The likelihood of a damaging earthquake in New York is small overall but the possibility is higher in the northern part of the state and in the New York City region. Significant earthquakes, both located in Rockaway and larger than magnitude 5, shook New York City in 1737 and 1884. The quakes were 147 years apart and the most recent was 122 year ago. It is likely that another earthquake of the same size will occur in that area in the next 25 to 50 years. A magnitude 5.8 earthquake in New York City would probably not cause great loss of life. However the damage to infrastructure – buildings, steam and gas lines, water mains, electric and fiber optic cable – could be extensive.

Earthquake Hazard Map of New York State

Acceleration of the ground during an earthquake is more important than total movement in causing structural damage. This map shows the two-percent probability of the occurrence of an earthquake that exceeds the acceleration of earth’s gravity by a certain percentage in the next fifty years.

If a person stands on a rug and the rug pulled slowly, the person will maintain balance and will not fall. But if the rug is jerked quickly, the person will topple. The same principle is true for building damage during an earthquake. Structural damage is caused more by the acceleration of the ground than by the distance the ground moves.

Earthquake hazard maps show the probability that the ground will move at a certain rate, measured as a percentage of earth’s gravity, during a particular time. Motion of one or two percent of gravity will rattle windows, doors, and dishes. Acceleration of ten to twenty percent of gravity will cause structural damage to buildings. It takes more than one hundred percent of gravity to throw objects into the air.

USGS: NYC Earthquake History Before The Sixth Seal

New York Earthquake History

Strong earthquakes in 1638, 1661, 1663, and 1732 in the St. Lawrence Valley and a shock near Newbury, Massachusetts, in 1727 were felt in New York before the first notable tremor centered within the State was recorded. On December 18, 1737, an earthquake near New York City threw down a number of chimneys (intensity VII). This shock was reported felt at Boston, Philadelphia, and at New Castle, Delaware.

Walls vibrated, bells rang, and objects fell from shelves (intensity VI) at Buffalo from a shock on October 23, 1857. Also, a man seated on a chair was reportedly thrown to the ground. At Lockport, rumbling noises were heard for a full minute. This shock was felt as far as Hamilton, Peterborough, and Port Hope, Ontario, Canada; Rochester, New York; and Erie and Warren, Pennsylvania. The total felt area covered approximately 46,000 square kilometers.

A rather severe earthquake centered in northeastern New York caused moderate damage along the St. Lawrence River and in the Lake Champlain area in 1877. Crockery was overturned, ceilings cracked, and chimneys were thrown down (intensity VII) from the November 4 tremor. At Saratoga Springs, buildings were shaken and a roaring sound was heard; at Auburn, windows were damaged. The earthquake was felt throughout a large part of New York and New England and eastern Canada, about 233,000 square kilometers.

On August 10, 1884, an earthquake caused large cracks in walls at Amityville and Jamaica (intensity VII). The shock was felt strongly at New York City. In addition, 30 towns from Hartford, Connecticut, to West Chester, Pennsylvania, reported fallen bricks and cracked plaster. The total felt area was estimated at 181,000 square kilometers.

A shock reported as severe, but with no damage noted (intensity VI), occurred in northeastern New York on May 27, 1897. It was felt over the greater portion of New York and parts of adjacent New England States and Quebec, Canada.

A very large area of the northeastern United States and eastern Canada, about 4,200,000 square kilometers, was shaken by a magnitude 7 earthquake on February 28, 1925 (March 1, universal time). A maximum intensity of VIII was reached in the epicentral region, near La Malbaie, Quebec, Canada. A large portion of New York State experienced intensity IV effects; lesser intensities were noted south of Albany.

Extensive damage occurred in the Attica area from a strong shock on August 12, 1929. Two hundred and fifty chimneys were thrown down, plaster was cracked or thrown down, and other building walls were noticeably damaged (intensity VIII). Many cemetery monuments fell or were twisted. Dishes fell from shelves, pictures and mirrors fell from walls, and clocks stopped. An increased flow at the Attica reservoir was noted for several days after the earthquake; a number of wells near the reservoir went dry. There was some damage at Batavia and other points at similar distances. A wall was cracked at Sayre, Pennsylvania. The earthquake was felt throughout most of New York and the New England states, northeastern Ohio, northern Pennsylvania, and southern Ontario, Canada; a total area of about 250,000 square kilometers. Strong aftershocks were felt at Attica on December 2 and 3; dishes fell from shelves and clocks stopped.

The opposite end of the State experienced similar damage from another shock less than 2 years later. On April 20, 1931, an earthquake centering near Lake George threw down about 20 chimneys at Warrensburg and twisted a church spire (intensity VII). A small landslide was reported on McCarthy Mountain. At Glen Falls, walls were cracked, dished broken, and clocks stopped. At Lake George, buildings swayed and store goods fell from shelves. At Luzerne, some Chimneys were damaged and windows broken. The shock was felt over 155,000 square kilometers, but with less intensity in the Catskills than at equal distances in other directions. This anomaly was also noted in the August 12, 1929, Attica earthquakes.

The magnitude 6 1/4 earthquake centered near Timiskaming, Quebec, Canada, on November 1, 1935, caused slight damaged at many points in New York. The damage was limited, in general, to plaster cracks, broken windows, and cracked chimneys. The shock was felt throughout New York, as far south as Washington, D.C., and as far west as Wisconsin. An earthquake centered near Lake Ossipee, New Hampshire on December 24, 1940, caused widespread, though slight, damage in the epicentral region, extending into Maine, Massachusetts, Rhode Island, and Vermont. Reports from Dannemora, New York, noted plaster and windows cracked and some dishes broken. The shock was felt over all of New York State.

On September 4, 1944, an earthquake centered about midway between Massena, New York, and Cornwall, Ontario, Canada, caused an estimated $2,000,000 damage in the two cities. The shock destroyed or damaged about 90 percent of the chimneys at Massena (intensity VIII), with similar effects at Cornwall. In addition, masonry, plumbing, and house foundations were damaged at Massena. Many structures were rendered unsage for occupancy until repaired. Press reports indicated a large number of wells in St. Lawrence County went dry, causing acute hardship. Brick masonry and concrete structures were damaged at Hogansburg; some ground cracking was also noted at nearby towns. This earthquake was felt over approximately 450,000 square kilometers in the United States, including all the New England States, Delaware, Maryland, New Jersey, Pennsylvania, and portions of Michigan and Ohio. A few points in Illinois, Indiana, Virginia, West Virginia, and Wisconsin also reported feeling the tremor.

A magnitude 4.7 disturbance on January 1, 1966, caused slight damage to chimneys and walls at Attica and Varysburg. Plaster fell at the Attica State Prison and the main smokestack was damaged (intensity VI). The total felt area was about 46,500 square kilometers.

Abridged from Earthquake Information Bulletin, Volume 7, Number 4, July – August 1975, by Carl A. von Hake.

For a list of earthquakes that have occurred since this article was written, use the Earthquake Search.

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

History Says New York Is Earthquake Prone

Fault Lines In New York City

Fault Lines In New York City

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)

The Sixth Seal: The Big Apple Shake (Rev 6:12)

Big Apple shake? Potential for earthquake in New York City exists

Posted 11:21 PM, April 2, 2014, by Jeremy Tanner and Mario Diaz

NEW YORK CITY (PIX11) — For the last 43 years John Armbruster has been a seismologist with Columbia University’s Lamont Doherty Earth Observatory. A veteran of what he describes as “a couple of dozen” quakes, he is interested in the seismic activity throughout the Pacific region in recent weeks.

However, does the amount of plate movements around the world in recent weeks as well as years to translate to New York City being more vulnerable, “These earthquakes are not communicating with each other, they are too far apart,” said Armbruster in an interview with PIX 11 News on Wednesday.

Nonetheless, Armbruster added that there are many faults around the area and a few in Manhattan, including on specific fault capable of producing a magnitude 6.0 earthquake, “The 125th street fault.”

What would a magnitude 6.0 earthquake inflict upon the city?

“I think there would be serious damage and casualties,” said Armbruster. The reason? Most of the buildings and infrastructure was not constructed to withstand earthquakes. This said, what does Armbruster think of the chances of a major earthquake catching New York City by surprise?

“We know that its unlikely because it hasn’t happened in the last 300 years but the earthquake that struck Fukushima Japan was the 1000 year earthquake and they weren’t ready for the that.

Preparing for the Sixth Seal (Revelation 6:12)

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


The Sixth Seal: NY City Destroyed

The Sixth Seal: NY City Destroyed

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.

The current efforts in the eastern U.S., including New York City, to start the enforcement of seismic building codes for new constructions are important first steps in the right direction. Similarly, the emerging efforts to include seismic rehabilitation strategies in the generally needed overhaul of the cities’ aged infrastructures such as bridges, water, sewer, power and transportation is commendable and needs to be pursued with diligence and persistence. But at the current pace of new construction replacing older buildings and lifelines, it will take many decades or a century before a major fraction of the stock of built assets will become seismically more resilient than the current inventory is. For some time, this leaves society exposed to very high seismic risks. The only consolation is that seismicity on average is low, and, hence with some luck, the earthquakes will not outpace any ongoing efforts to make eastern cities more earthquake resilient gradually. Nevertheless, M = 5 to M = 6 earthquakes at distances of tens of km must be considered a credible risk at almost any time for cities like Boston, New York or Philadelphia. M = 7 events, while possible, are much less likely; and in many respects, even if building codes will have affected the resilience of a future improved building stock, M = 7 events would cause virtually unmanageable situations. Given these bleak prospects, it will be necessary to focus on crucial elements such as maintaining access to cities by strengthening critical bridges, improving the structural and nonstructural performance of hospitals, and having a nationally supported plan how to assist a devastated region in case of a truly severe earthquake. No realistic and coordinated planning of this sort exists at this time for most eastern cities.

The current efforts by the Federal Emergency Management Administration (FEMA) via the National Institute of Building Sciences (NIBS) to provide a standard methodology (RMS, 1994) and planning tools for making systematic, computerized loss estimates for annualized probabilistic calculations as well as for individual scenario events, is commendable. But these new tools provide only a shell with little regional data content. What is needed are the detailed data bases on inventory of buildings and lifelines with their locally specific seismic fragility properties. Similar data are needed for hospitals, shelters, firehouses, police stations and other emergency service providers. Moreover, the soil and rock conditions which control the shaking and soil liquefaction properties for any given event, need to be systematically compiled into Geographical Information System (GIS) data bases so they can be combined with the inventory of built assets for quantitative loss and impact estimates. Even under the best of conceivable funding conditions, it will take years before such data bases can be established so they will be sufficiently reliable and detailed to perform realistic and credible loss scenarios. Without such planning tools, society will remain in the dark as to what it may encounter from a future major eastern earthquake. Given these uncertainties, and despite them, both the public and private sector must develop at least some basic concepts for contingency plans. For instance, the New York City financial service industry, from banks to the stock and bond markets and beyond, ought to consider operational contingency planning, first in terms of strengthening their operational facilities, but also for temporary backup operations until operations in the designated facilities can return to some measure of normalcy. The Federal Reserve in its oversight function for this industry needs to take a hard look at this situation.

A society, whose economy depends increasingly so crucially on rapid exchange of vast quantities of information must become concerned with strengthening its communication facilities together with the facilities into which the information is channeled. In principle, the availability of satellite communication (especially if self-powered) with direct up and down links, provides here an opportunity that is potentially a great advantage over distributed buried networks. Distributed networks for transportation, power, gas, water, sewer and cabled communication will be expensive to harden (or restore after an event).

In all future instances of major capital spending on buildings and urban infrastructures, the incorporation of seismically resilient design principles at all stages of realization will be the most effective way to reduce society’s exposure to high seismic risks. To achieve this, all levels of government need to utilize legislative and regulatory options; insurance industries need to build economic incentives for seismic safety features into their insurance policy offerings; and the private sector, through trade and professional organizations’ planning efforts, needs to develop a healthy self-protective stand. Also, the insurance industry needs to invest more aggressively into broadly based research activities with the objective to quantify the seismic hazards, the exposed assets and their seismic fragilities much more accurately than currently possible. Only together these combined measures may first help to quantify and then reduce our currently untenably large seismic risk exposures in the virtually unprepared eastern cities. Given the low-probability/high-impact situation in this part of the country, seismic safety planning needs to be woven into both the regular capital spending and daily operational procedures. Without it we must be prepared to see little progress. Unless we succeed to build seismic safety considerations into everyday decision making as a normal procedure of doing business, society will lose the race against the unstoppable forces of nature. While we never can entirely win this race, we can succeed in converting unmitigated catastrophes into manageable disasters, or better, tolerable natural events.

Authorities Expecting The Sixth Seal? (Rev 6:12)


US Raises Threat of Quake but Lowers Risk for Towers

New York Times


JULY 17, 2014
Here is another reason to buy a mega-million-dollar apartment in a Manhattan high-rise: Earthquake forecast maps for New York City that a federal agency issued on Thursday indicate “a slightly lower hazard for tall buildings than previously thought.”

The agency, the United States Geodetic Survey, tempered its latest quake prediction with a big caveat.

“The eastern U.S. has the potential for larger and more damaging earthquakes than considered in previous maps and assessments,” the agency said, citing the magnitude 5.8 quake that struck Virginia in 2011.

Federal seismologists based their projections of a lower hazard for tall buildings — “but still a hazard nonetheless,” they cautioned — on a lower likelihood of slow shaking from an earthquake occurring near the city, the type of shaking that typically causes more damage to taller structures.

“The tall buildings in Manhattan are not where you should be focusing,” said John Armbruster, a seismologist with the Lamont-Doherty Earth Observatory of Columbia University. “They resonate with long period waves. They are designed and engineered to ride out an earthquake. Where you should really be worried in New York City is the common brownstone and apartment building and buildings that are poorly maintained.”

Mr. Armbruster was not involved in the federal forecast, but was an author of an earlier study that suggested that “a pattern of subtle but active faults makes the risk of earthquakes to the New York City area substantially greater than formerly believed.”

He noted that barely a day goes by without a New York City building’s being declared unsafe, without an earthquake. “If you had 30, 40, 50 at one time, responders would be overloaded,” he said.

The city does have an earthquake building code that went into effect in 1996, and that applies primarily to new construction.

A well-maintained building would probably survive a magnitude 5 earthquake fairly well, he said. The last magnitude 5 earthquake in the city struck in 1884. Another is not necessarily inevitable; faults are more random and move more slowly than they do in, say, California. But he said the latest federal estimate was probably raised because of the magnitude of the Virginia quake.

“Could there be a magnitude 6 in New York?” Mr. Armbruster said. “In Virginia, in a 300 year history, 4.8 was the biggest, and then you have a 5.8. So in New York, I wouldn’t say a 6 is impossible.

Mr. Armbruster said the Geodetic Survey forecast would not affect his daily lifestyle. “I live in a wood-frame building with a brick chimney and I’m not alarmed sitting up at night worried about it,” he said. “But society’s leaders need to take some responsibility.

Scientists Expecting the Sixth Seal

Scientists find likely cause of 2011 Virginia earthquake, believe there may be more to come


August 19, 2016; 3:59 AM

On Aug. 23, 2011, those living in eastern North America, from Ontario to Georgia, felt an unexpected shock as the earth trembled in the wake of a 5.8 magnitude earthquake that struck near the town of Mineral, Virginia, around 2 p.m. local time.

A notable quake with a magnitude of 4.0 or higher east of the Rockies is a rarity, according to USGS reports.

However, a recent study published in the Journal of Geophysical Research – Solid Earth is shedding light on the likely causes behind the event and may indicate that there are more to come.

Unlike earthquakes that occur near plate boundaries in the more seismically active regions of the world, the 2011 quake raised questions among researchers and stirred alarm among those living in the Washington, D.C., area who felt its full force.

According to the American Geophysical Union, the journal’s parent organization, researchers have discovered pieces of the mantle have been breaking off below the North American Plate in this region and sinking deeper into the earth.

Our idea supports the view that this seismicity will continue due to unbalanced stresses in the plate,” Berk Biryol told the AGU.

Biryol is a seismologist at the University of North Carolina Chapel Hill and lead author of the recently published study. According to Biryol’s research, the geological processes the researchers found revealed thinning and weakening of the plate.

While most earthquakes tend to occur at subduction zones, or near plate boundaries, the processes causing the earthquakes in the middle of plates have often remained a mystery to scientists.

In order to figure out what was happening deep below the Earth’s surface, Biryol and the study’s team had to use seismic waves generated by earthquakes as far as 2,200 miles away to create a 3D map of the region by tracing the paths of the waves as they moved through the ground.

Virginia along with the rest of the North American continent, Greenland and portions of the Atlantic and Arctic oceans are all located on the vast North American Plate. The plate rides on thin, heated layer of viscous rock called the asthenosphere.

Biryol’s study, which found varying, uneven plate thickness, and a mix of older rock and younger rock, may now help solve many of the mysteries behind tectonic plates’ interactions with the asthenosphere.

“At certain times, the densest parts broke off from the plate and sank into the warm asthenosphere below,” the AGU reported.

“The asthenosphere, being lighter and more buoyant, surged in to fill the void created by the missing pieces of mantle, eventually cooling to become the thin, young rock.”

Coupled with the thinning and weakening of the plate, ancient fault lines long considered stable become more susceptible to slipping, which leads to earthquakes, according the AGU.

The new study unveils that there is much more going on deep beneath the Earth’s surface than scientists originally thought, and that pieces of the mantle have likely been breaking off under the plate for nearly 65 million years.

As the research on these occurrences continues, scientists may gain a better understanding on where these earthquakes will likely occur.

Biryol told the AGU that these seismic zones will remain active over time and will likely cause additional earthquakes in the future.

The Sixth Seal: The Big Apple Shake (Rev 6:12)

Big Apple shake? Potential for earthquake in New York City exists

NY bridge

NEW YORK CITY (PIX11) – For the last 43 years John Armbruster has been a seismologist with Columbia University’s Lamont Doherty Earth Observatory.  A veteran of what he describes as “a couple of dozen” quakes, he is interested in the seismic activity throughout the Pacific region in recent weeks.

However, does the amount of plate movements around the world in recent weeks as well as years to translate to New York City being more vulnerable, “These earthquakes are not communicating with each other, they are too far apart,” said Armbruster in an interview with PIX 11 News on Wednesday.

Nonetheless, Armbruster added that there are many faults around the area and a few in Manhattan, including on specific fault capable of producing a magnitude 6.0 earthquake, “The 125th street fault.”

What would a magnitude 6.0 earthquake inflict upon the city?

“I think there would be serious damage and casualties,” said Armbruster.  The reason?  Most of the buildings and infrastructure was not constructed  to withstand earthquakes.  This said, what does Armbruster think of the chances of a major earthquake catching New York City by surprise?

“We know that its unlikely because it hasn’t happened in the last 300 years but the earthquake that struck Fukushima Japan was the 1000 year earthquake and they weren’t ready for the that.

What Will Happen At The Sixth Seal (Revelation 6:12)

What If The Earthquake Had Hit Manhattan?

Today’s 5.9 magnitude earthquake was felt throughout the mid-Atlantic, but its epicentre — a small town in Virginia — took the brunt of its wrath. What if it had started in NYC instead? We may find out sooner than you think.

The Risk Is Real

New York isn’t very high on the list of places you think of when you think earthquake. But that’s more a lucky accident of the times we live in than a promise of future calm. In the 400 years that we’ve inhabited that small, skinny island off the coast of New Jersey, the city’s been hit at least three times by moderate-to-major earthquakes. A 1737 quake just outside the city limits shook chimneys to the ground. Another struck in 1783. And in 1884, a 5.5-magnitude event cracked the walls of buildings in Jamaica and was felt as far away as Maine. Historically speaking, we’re overdue.

Scientifically speaking, too. A 2008 report in the Bulletin of the Seismological Society of America (PDF) showed that those three were just the perceptible earthquakes suffered by the region; a total of 383 tremors and shakes have occurred in the 39,000sqkm area around NYC since 1677. New York and its environs sit atop a vast networks of several small, active faults and a handful of lines capable of producing 6 and 7 magnitude events that have lain dormant. For now.

Best Case Scenario

The most likely occurrence — a 5ish magnitude quake in or near Manhattan — would be terrifically bad. Not end-of-the-world bad. Not cataclysmic. But horribly traumatic, according to a 2005 study by the New York City Area Consortium for Earthquake Loss Mitigation. The committee, a group of civil engineers, academics, and government officials, spent four years determining the fallout of a significant NYC quake. Let’s hope we never find out if they were right.

I spoke with Dan O’Brian, a Program Manager for the NYS Office of Emergency Management and one of the co-authors of that report. He said that while it was published in 2005, the findings largely hold true six years later. And that the biggest risk isn’t the city’s the towering skyscrapers; it’s the brownstones:

The [structures]that are of a particular concern are unreinforced masonry. The brownstones, six-story, turn of the century. Those are the buildings that don’t have much ability to withstand lateral forces, and they tend to crumble.

So what kind of damage are we talking about? According to the NYCEM report, an event of equal strength to what hit Virginia today would cost approximately $US45 billion (inflation adjusted) in building damage and lost income, with over 2500 buildings damaged and nearly 200,000 people left homeless. Forty tons of debris would cascade the streets, 25 times the amount caused by 9/11. The casualties: 1200 dead, 200,000 wounded.

“You’ve got so much there, if you were to have an epicentre of even a moderate sized earthquake, if it’s epicentered in the immediate NY area you’re likely to see a good bit of damage,” explains O’Brien. Most of that is due to the general building stock.”

The destruction wouldn’t be evenly distributed. Softer soil leads to stronger vibrations; that geological truth, combined with where most of that unreinforced masonry stock is located, make the Upper East Side and Chinatown most vulnerable to a quake. The city’s skyscrapers will hold (to a point), the bridges will survive as well today as they did in 1884. There would be nearly a thousand fires, but the NYFD would have the resources to handle them–assuming the water lines aren’t cut in the quake.

So yes, bad, right. But not doomsday. Although that’s an option, too.

Worst Case Scenario

Did you know that New York City sits less than 40km away from an active nuclear power plant? And that that same power plant sits just a mile south of an active seismic zone that’s considered capable of causing a 6.0-magnitude earthquake? That’s when things get apocalyptic.

The Indian Point nuclear plant, located just north of Manhattan, has provided power to Westchester County and the city itself for decades without incident. But while its operators have claimed that the structures can survive up to a magnitude 6 quake, seismologist Lynn Sykes told the Gotham Gazette recently that he isn’t so sure:

The plants are designed to withstand an event on the intensity scale of VII, which equals a magnitude of 5 or slightly higher in the region. (Intensity measures the effects on people and structures.) A magnitude 6 quake, in Sykes opinion, would indeed cause damage to the plant.

The two reactors provide 10 per cent of the state’s electricity and 30 per cent of NYC’s, meaning that in addition to the destruction outlined in our best case scenario, massive power outages could be expected. If the quake were strong enough to create fractures in Indian Point’s bedrock, radioactive materials could flow freely into the Hudson River. After the events of Fukushima earlier this year, that’s no longer an unthinkable occurrence.

So where does that leave us? We’re in no better or worse shape today than we were yesterday or last month. And the only part of this equation that might change in the next several years is Indian Point, which has been facing political pressure of late and whose contract may not be renewed. But really, the only thing that’s different now is the awareness that it’s not an if, it’s a when. That we’re just running out the clock. And that’s should have us shaking in our boots.

The Sixth Seal: Real Risk, Few Precautions (Revelation 6:12)

Eastern Quakes: Real Risk, Few Precautions

1989 San Francisco Earthquake

1989 San Francisco Earthquake

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.”

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.”