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Earthquakes in New York City
Engineering Geology, 29 (1990) 185-189 Elsevier SciencePublishers B.V.,Amsterdam-- Printed in The Netherlands
185
Opinion Section Earthquakes in New York City Ellis L. Krinitzsky and Patrick J. Barosh Department of Geology, Texas A & M University, College Station, Texas 77843-3115 (U.S.A.) Barosh & Associates, 35 Potter St., Concord, Massachusetts, 01742 (U.S.A.) (Accepted for publication October 17, 1989) Can New York City be destroyed by an earthquake? Will the city tumble down any day now? Will its civilization be blotted out? Are those questions exaggerated? Not if you listened to American television recently. Views of an imminent disaster were aired by the National Broadcasting Corporation in a Special Report on Earthquakes shown during February 27 through March 1, 1989. The principal protagonists were: Chuck Scarborough, NBC Klaus Jacob, Lamont-Doherty Geological Observatory Robert Ketter, National Center for Earthquake Engineering Charles Merguerian, Hofstra University These are some of their statements: Scarborough: ...New York is on the earthquake hit list. In fact, far more vulnerable than California. Not even a matter of scientific debate. Earthquake experts and geologists are certain. Awfully strong! We assume Scarborough only repeated what his experts told him. His experts added: Jacob: It's inevitable that New York City, and by the way, Boston and several other cities on the East Coast, sooner or later will be hit. It's just a matter o f when. Ketter: We're past due for one on the East Coast, of major consequence. Then Scarborough described a seismograph and added: Scarborough: In a span of 30 seconds it (the seismograph needle) will have written what couM be the final chapter in the history o f New York. Then Jacob: Cities have been killed by earthquakes in the past. Honestly, it's not clear whether New York will survive as a city with its economy and cultural assets as we know them. Merguerian: What's the worst case? The worst case scenario is a city that is burned down. A population that attempts toffee and can't get off the island. Total breakdown o f medical services. Total breakdown of police protection and enforcement. And then on top of that a nuclear residue floating down the Hudson River. I mean, how much worse can it get? Scarborough: ...Add to all that the horrifying thought that a nuclear power plant, just north of the city, is sitting directly on top of a major fault. The program was designed to have a strong impact. These statements were 0013-7952/90/$03.50
© 1990 ElsevierSciencePublishers B.V.
186
E.L. KRINITZSKY AND P.J. BAROSH
interspersed with views of the recent devastation in Armenia, of San Francisco burned out in 1906, and collapsed buildings in Mexico City in 1985, after each of which they cut back to New York City. It was New York City that was their center of concern and it is easy for viewers to not realize that their examples had nothing to do with New York City. There is no San Andreas fault in New York City. There is no moving plate boundary as in Armenia. There are no soft lake bed sediments as in Mexico City. To make those comparisons can only mislead the public. And it went on: Scarborough: Recall the freeways of Los Angeles that buckled like matchsticks. What will become of our roadways, our airport runways, bridges, and tunnels? Merguerian: You don't need to be trained to see that the tunnel (viewing a geological section of a subway tunnel) passes through one fracture zone, disintegrated rock zone, evidently a fault, second fault there, third fault there. The fact that the tunnels run through different types of materials, um, that the tunnels will probably snap like glass tubes. Tunnels are the safest places to be during earthquakes. During the Mexico earthquake, the subway system was never put out of commission. In Tangshan, China, when a recent great earthquake killed more than 250,000 people, the devastation occurred above a maze of coal mines. Faults moved within those mines. Yet, in the mines there was little damage and no direct deaths from the earthquake. The miners were shocked when they came to the surface and saw the destruction in Tangshan. But in New York, there are no faults that are moving. This sort of overstatement has been going on for a long while and by others as well. A famous example is a letter sent by James F. Devine of the U.S. Geological Survey to Robert E. Jackson at the Nuclear Regulatory Commission on 18 November 1982. It said: Because the geologic and tectonic features of the Charleston (South Carolina) region are similar to those in other regions of the eastern seaboard, we conclude that although there is no recent or historical evidence that other regions have experienced strong earthquakes...(we cannot rule) out the occurrence in these other regions of strong seismic ground motions similar to those experienced near Charleston in 1886. In effect, the letter said that a Charleston earthquake, the severest that occurred in the Eastern Seaboard, can possibly happen again anywhere in the Eastern Seaboard. The letter contains a glaring error. The geologic and tectonic features of the Charleston region are absolutely not similar to those of everywhere in the Eastern Seaboard. Microearthquake and felt earthquakes show that earthquake source zones are greatly restricted in eastern United States and the source zone in the Charleston area is unique to that area. (For a discussion of the tectonic controls see Barosh, 1986.) Nonetheless, the Nuclear Regulatory Commission and the Electric Power Research Institute were obliged by that letter to spend millions of dollars on fruitless investigations. And that is the problem with all of these allegations. It is the waste that they cause and their costs to society. Unfortunately, there is a desperate need in all of the United States for earthquake awareness and for earthquake preparedness. Those needs are not helped by overemphasis and false statements concerning potential earthquakes. Preparedness
EARTHQUAKES IN NEW YORK CITY
187
that is appropriate to the threat is not carried out. Instead, scarce funds are diverted into fruitless studies and improper evaluations. And society is penalized in other ways as well. Irresponsible allegations of the sort described above have been particularly detrimental to the nuclear power industry. They have helped to kill that industry in the United States, though nuclear power is thriving in the rest of the world including areas with potentials for severe earthquakes. What then is really the earthquake hazard at New York City? Let us examine it. Fig.1 shows the major faults and the historic earthquakes from 1677 to 1980. The largest earthquake occurring at New York City is an event of epicentral Modified
75=001
74°001
41°301
41"001
40"3d
LEGEND MM INTENSITY A Z~ Z~
II III IV
Z~
v
/~
VI f
0 i
10
0 i
3
NUMBER OF EQKS
o
NO INTENSITY /
20
20
80 MILES 40 KM
FAULT, DASHED WHERE INFERRED
Fig.l. The Ramapo fault and felt earthquakes in relation to New York City, modified from Krinitzsky 0986).
188
E.L. K R I N I T Z S K Y A N D P.J. B A R O S H
Mercalli intensity VI that occurred on 10 August 1884. See Nottis and Mitronovas (1983), Barosh (1984, 1986) and Krinitzsky (1986) for a full earthquake history and interpretation of potential hazard. M M VI is a shake that could hardly damage even faulty construction, and then only if it is on soft ground, but is of no hazard otherwise unless the building was about to fall down anyway. Most of New York City is on bedrock though there are small areas of soft foundations. The R a m a p o fault is highlighted because for m a n y years it has been a target only because it is located near the Indian Point Nuclear Power Plant. However, the R a m a p o fault has not moved since the Upper Cretaceous, about 90 million years ago (see Dames and Moore, 1977; Krinitzsky, 1986). Let us look at earthquake ground motions that have been postulated for New York City. Fig.2 shows mean horizontal acceleration on rock for eastern United States prepared by Algermissen et al. (1982). They appear to have done no
1 4 5°
4o°
3s°
3o°
2s°
~
WU
O0
OU
ID
Fig.2. Interpreted mean horizontal accelerations from earthquakes for a 250-year period with 90% nonexceedence in eastern United States. Adapted from Algermissenet al. (1982).
EARTHQUAKES IN NEW YORK CITY
189
independent work on earthquake sources, but responded to the allegations that have been made for years in this area. Note the acceleration they gave for the area of the Ramapo fault. It is an incredible 0.54 G. That is two-thirds of what they estimate for New Madrid, Missouri, where in 1811-12 there occurred earthquakes of M M XI to XII that were felt over all of eastern United States and into Canada. Also, the Ramapo fault area is given twice the motion for Charleston, South Carolina, where in 1886 the severest earthquake in the eastern seaboard occurred with an MM intensity of X. This mean value of 0.54 G on rock is postulated for a fault that has not moved in 90 million years and is in a seismic region for which the maximum epicentral intensity for earthquakes is M M VI. New York City and other urban areas of the eastern United States are in the process of developing guidelines for desirable levels of seismic safety. But what are the levels? What should they be? Here is where the real cost to society will occur. Here is where fallacious allegations, such as we examined here, can exact a terrible price. REFERENCES Algermissen, S.T., Perkins, D.M., Thenhaus, P.C., Hanson, S.L. and Bender, B.L., 1982. Probabilistic estimates of maximum acceleration and velocity in rock in the contiguous United States. U.S. Geol. Surv., Open-File Rept., 80-1033. Barosh, P.J., 1984. Earthquake controls and zonation in New York. U. S. Geol. Surv., Open-File Rept., 85-386: 54-75. Barosh, P.J., 1986. Neotectonic movement, earthquakes and stress state in the eastern United States. Tectonophysics, 132:117-152. Dames and Moore Consultants, 1977. Geotechnical Investigation of the Ramapo Fault Systems in the Region of the Indian Point Generating Station. Vols. I and II, prepared for the Consolidated Edison Company, New York, N.Y. Krinitzsky, Ellis, L., 1986. Geological-seismological evaluation of earthquake hazards at Prompton and Francis E. Walter damsites, Pennsylvania. Tech. Rept. GL-86-8, Waterways Experiment Station, Vicksburg, Miss. Nottis, G.N. and Mitronovas, W., 1983. Documentation of the felt earthquakes in the coastal plain of southeastern New York and east-central New Jersey: 1847-1954. U.S. Nuclear Regulatory Commission Rept., NRC B 5961, 74 pp.
185
Opinion Section Earthquakes in New York City Ellis L. Krinitzsky and Patrick J. Barosh Department of Geology, Texas A & M University, College Station, Texas 77843-3115 (U.S.A.) Barosh & Associates, 35 Potter St., Concord, Massachusetts, 01742 (U.S.A.) (Accepted for publication October 17, 1989) Can New York City be destroyed by an earthquake? Will the city tumble down any day now? Will its civilization be blotted out? Are those questions exaggerated? Not if you listened to American television recently. Views of an imminent disaster were aired by the National Broadcasting Corporation in a Special Report on Earthquakes shown during February 27 through March 1, 1989. The principal protagonists were: Chuck Scarborough, NBC Klaus Jacob, Lamont-Doherty Geological Observatory Robert Ketter, National Center for Earthquake Engineering Charles Merguerian, Hofstra University These are some of their statements: Scarborough: ...New York is on the earthquake hit list. In fact, far more vulnerable than California. Not even a matter of scientific debate. Earthquake experts and geologists are certain. Awfully strong! We assume Scarborough only repeated what his experts told him. His experts added: Jacob: It's inevitable that New York City, and by the way, Boston and several other cities on the East Coast, sooner or later will be hit. It's just a matter o f when. Ketter: We're past due for one on the East Coast, of major consequence. Then Scarborough described a seismograph and added: Scarborough: In a span of 30 seconds it (the seismograph needle) will have written what couM be the final chapter in the history o f New York. Then Jacob: Cities have been killed by earthquakes in the past. Honestly, it's not clear whether New York will survive as a city with its economy and cultural assets as we know them. Merguerian: What's the worst case? The worst case scenario is a city that is burned down. A population that attempts toffee and can't get off the island. Total breakdown o f medical services. Total breakdown of police protection and enforcement. And then on top of that a nuclear residue floating down the Hudson River. I mean, how much worse can it get? Scarborough: ...Add to all that the horrifying thought that a nuclear power plant, just north of the city, is sitting directly on top of a major fault. The program was designed to have a strong impact. These statements were 0013-7952/90/$03.50
© 1990 ElsevierSciencePublishers B.V.
186
E.L. KRINITZSKY AND P.J. BAROSH
interspersed with views of the recent devastation in Armenia, of San Francisco burned out in 1906, and collapsed buildings in Mexico City in 1985, after each of which they cut back to New York City. It was New York City that was their center of concern and it is easy for viewers to not realize that their examples had nothing to do with New York City. There is no San Andreas fault in New York City. There is no moving plate boundary as in Armenia. There are no soft lake bed sediments as in Mexico City. To make those comparisons can only mislead the public. And it went on: Scarborough: Recall the freeways of Los Angeles that buckled like matchsticks. What will become of our roadways, our airport runways, bridges, and tunnels? Merguerian: You don't need to be trained to see that the tunnel (viewing a geological section of a subway tunnel) passes through one fracture zone, disintegrated rock zone, evidently a fault, second fault there, third fault there. The fact that the tunnels run through different types of materials, um, that the tunnels will probably snap like glass tubes. Tunnels are the safest places to be during earthquakes. During the Mexico earthquake, the subway system was never put out of commission. In Tangshan, China, when a recent great earthquake killed more than 250,000 people, the devastation occurred above a maze of coal mines. Faults moved within those mines. Yet, in the mines there was little damage and no direct deaths from the earthquake. The miners were shocked when they came to the surface and saw the destruction in Tangshan. But in New York, there are no faults that are moving. This sort of overstatement has been going on for a long while and by others as well. A famous example is a letter sent by James F. Devine of the U.S. Geological Survey to Robert E. Jackson at the Nuclear Regulatory Commission on 18 November 1982. It said: Because the geologic and tectonic features of the Charleston (South Carolina) region are similar to those in other regions of the eastern seaboard, we conclude that although there is no recent or historical evidence that other regions have experienced strong earthquakes...(we cannot rule) out the occurrence in these other regions of strong seismic ground motions similar to those experienced near Charleston in 1886. In effect, the letter said that a Charleston earthquake, the severest that occurred in the Eastern Seaboard, can possibly happen again anywhere in the Eastern Seaboard. The letter contains a glaring error. The geologic and tectonic features of the Charleston region are absolutely not similar to those of everywhere in the Eastern Seaboard. Microearthquake and felt earthquakes show that earthquake source zones are greatly restricted in eastern United States and the source zone in the Charleston area is unique to that area. (For a discussion of the tectonic controls see Barosh, 1986.) Nonetheless, the Nuclear Regulatory Commission and the Electric Power Research Institute were obliged by that letter to spend millions of dollars on fruitless investigations. And that is the problem with all of these allegations. It is the waste that they cause and their costs to society. Unfortunately, there is a desperate need in all of the United States for earthquake awareness and for earthquake preparedness. Those needs are not helped by overemphasis and false statements concerning potential earthquakes. Preparedness
EARTHQUAKES IN NEW YORK CITY
187
that is appropriate to the threat is not carried out. Instead, scarce funds are diverted into fruitless studies and improper evaluations. And society is penalized in other ways as well. Irresponsible allegations of the sort described above have been particularly detrimental to the nuclear power industry. They have helped to kill that industry in the United States, though nuclear power is thriving in the rest of the world including areas with potentials for severe earthquakes. What then is really the earthquake hazard at New York City? Let us examine it. Fig.1 shows the major faults and the historic earthquakes from 1677 to 1980. The largest earthquake occurring at New York City is an event of epicentral Modified
75=001
74°001
41°301
41"001
40"3d
LEGEND MM INTENSITY A Z~ Z~
II III IV
Z~
v
/~
VI f
0 i
10
0 i
3
NUMBER OF EQKS
o
NO INTENSITY /
20
20
80 MILES 40 KM
FAULT, DASHED WHERE INFERRED
Fig.l. The Ramapo fault and felt earthquakes in relation to New York City, modified from Krinitzsky 0986).
188
E.L. K R I N I T Z S K Y A N D P.J. B A R O S H
Mercalli intensity VI that occurred on 10 August 1884. See Nottis and Mitronovas (1983), Barosh (1984, 1986) and Krinitzsky (1986) for a full earthquake history and interpretation of potential hazard. M M VI is a shake that could hardly damage even faulty construction, and then only if it is on soft ground, but is of no hazard otherwise unless the building was about to fall down anyway. Most of New York City is on bedrock though there are small areas of soft foundations. The R a m a p o fault is highlighted because for m a n y years it has been a target only because it is located near the Indian Point Nuclear Power Plant. However, the R a m a p o fault has not moved since the Upper Cretaceous, about 90 million years ago (see Dames and Moore, 1977; Krinitzsky, 1986). Let us look at earthquake ground motions that have been postulated for New York City. Fig.2 shows mean horizontal acceleration on rock for eastern United States prepared by Algermissen et al. (1982). They appear to have done no
1 4 5°
4o°
3s°
3o°
2s°
~
WU
O0
OU
ID
Fig.2. Interpreted mean horizontal accelerations from earthquakes for a 250-year period with 90% nonexceedence in eastern United States. Adapted from Algermissenet al. (1982).
EARTHQUAKES IN NEW YORK CITY
189
independent work on earthquake sources, but responded to the allegations that have been made for years in this area. Note the acceleration they gave for the area of the Ramapo fault. It is an incredible 0.54 G. That is two-thirds of what they estimate for New Madrid, Missouri, where in 1811-12 there occurred earthquakes of M M XI to XII that were felt over all of eastern United States and into Canada. Also, the Ramapo fault area is given twice the motion for Charleston, South Carolina, where in 1886 the severest earthquake in the eastern seaboard occurred with an MM intensity of X. This mean value of 0.54 G on rock is postulated for a fault that has not moved in 90 million years and is in a seismic region for which the maximum epicentral intensity for earthquakes is M M VI. New York City and other urban areas of the eastern United States are in the process of developing guidelines for desirable levels of seismic safety. But what are the levels? What should they be? Here is where the real cost to society will occur. Here is where fallacious allegations, such as we examined here, can exact a terrible price. REFERENCES Algermissen, S.T., Perkins, D.M., Thenhaus, P.C., Hanson, S.L. and Bender, B.L., 1982. Probabilistic estimates of maximum acceleration and velocity in rock in the contiguous United States. U.S. Geol. Surv., Open-File Rept., 80-1033. Barosh, P.J., 1984. Earthquake controls and zonation in New York. U. S. Geol. Surv., Open-File Rept., 85-386: 54-75. Barosh, P.J., 1986. Neotectonic movement, earthquakes and stress state in the eastern United States. Tectonophysics, 132:117-152. Dames and Moore Consultants, 1977. Geotechnical Investigation of the Ramapo Fault Systems in the Region of the Indian Point Generating Station. Vols. I and II, prepared for the Consolidated Edison Company, New York, N.Y. Krinitzsky, Ellis, L., 1986. Geological-seismological evaluation of earthquake hazards at Prompton and Francis E. Walter damsites, Pennsylvania. Tech. Rept. GL-86-8, Waterways Experiment Station, Vicksburg, Miss. Nottis, G.N. and Mitronovas, W., 1983. Documentation of the felt earthquakes in the coastal plain of southeastern New York and east-central New Jersey: 1847-1954. U.S. Nuclear Regulatory Commission Rept., NRC B 5961, 74 pp.