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Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

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At least 37 records · Page 2Linked to original sources
USGS1976

Earthquake history of Pennsylvania

Record of early earthquakes in Northeastern United States provide limited information on effects in pennsylvania until 1737, 55 years after the first permanent settlement was established. A very severe earthquake that centered in the St.Lawrence River region in 1663 may have been felt in Pennsylvania, but historical accounts are not definite. Likewise, a damaging shock at Newbury, Mass., in 1727 probably affected towns in Pennsylvania. A strong earthquake on December 18, 1737, toppled chimneys at New York City and was reported felt at Boston, Mass., Philadelphia, Pa. and New Castle, Del. Other shocks with origins outside the State were felt in 1758, 1783, and 1791. Since 1800, when two earthquakes (March 17 and November 29) were reported as "severe" at Philadelphia, 16 tremors of intensity V or greater (Modified Mercalli Scale) have originated within the State. On November 11 and 14, 1840, sever earthquakes at Philadelphia were accompnaied by a great and unusual swell on the Delaware River.

Pennsylvania↗
USGS1976

Earthquake history of Oregon

Although situated between two States (California and Washington) that have has many violent earthquakes, Oregon is noticeably less active seismically. the greatest damage experienced resulted from a major shock near Olympia, Wash., in 1949. During the short history record available (since 1841), 34 earthquakes of intensity V, Modified Mercalli Scale, or greater have centered within Oregon or near its borders. Only 13 of the earthquakes had an intensity above V, and many of the shocks were local. However, a 1936 earthquake in the eastern Oregon-Washington region caused extensive damage and was felt over an area of 272,000 square kilometers.

Oregon↗
USGS1976

Earthquake history of Oklahoma

The strongest and most widely felt earthquake in Oklahoma occurred on April 9, 1952. The intensity VII (Modified Mercalli Scale) tremor was felt over 362,000 sqaure kilometres. A second intensity VII earthquake, felt over a very small area, occurred in October 1956. In addition, 15 other shocks, intensity V or VI, have originated within Oklahoma.

Oklahoma↗
USGS1975

Earthquake history of New Mexico

Most of New Mexico's historical seismcity has been concentrated in the Rio Grande Valley between Socorro and Albuquerque. About half of the earthquakes of intensity V or greater (Modified Mercalli intensity) that occurred in teh State between 1868 and 1973 were centered in this region.

New Mexico↗
USGS1974

Earthquake history of Nevada

Since 1852, more than 30 shocks of intensity VI or greater (Modified Mercalli scale) have occurred in western Nevada. At least three of these were classified as intensity X. In addition, seven earthquakes (intensity VI or greater) were centered in the eastern part of the State. Almost 2,000 other shocks have been cataloged in the nearly 125-year period of historical records. Thus, Nevada ranks among the most seismically active States.

Nevada↗
USGS1974

Earthquake history of Nebraska

Nebraska is in a region of moderate seismicity occasionally punctuated by rather strong earthquakes. Most of the State is seismic risk zone 1, with a small part in the southeast corner in risk zone 2. the first significant earthquake felt in Nebraska occurred in 1867, the year that statehood was achieved. the tremor occurred on April 24, 1867, and was apparently centered near Lawrence, Kansas. It affected an area estimated at 780,000 km 2 including much of Nebraska. Since 1867, at least seven earthquakes of intensity V or greater have originated within Nebraska's boundaries. Several strong earthquakes centered in neighboring States have also been felt over limited portions of Nebraska. None of these caused damage.

Nebraska↗
USGS1978

Sea-level changes before large earthquakes

Changes in sea level have long been used as a measure of local uplift and subsidence associated with large earthquakes. For instance, in 1835, the British naturalist Charles Darwin observed that sea level dropped by 2.7 meters during the large earthquake in Concepcion, CHile. From this piece of evidence and the terraces along the beach that he saw, Darwin concluded that the Andes had grown to their present height through earthquakes. Much more recently, George Plafker and James C. Savage of the U.S Geological Survey have shown, from barnacle lines, that the great 1960 Chile and the 1964 Alaska earthquakes caused several meters of vertical displacement of the shoreline.

Earthquake Information Bulletin (USGS)↗
USGS1976

Geothermal energy in the United States; Part II, Assessment of resources

Geothermal energy-from heat deep inside the Earth- is a vast potential source of power. This article is the second part of a series on geothermal energy, the first part of which was in volume 8, number 1, of the Earthquake Information Bulletin (January-February 1976). Part 1 of this series described the categories of the geothermal resource base.

Earthquake Information Bulletin (USGS)↗
USGS1981

The U.S. Earthquake Prediction Program

Following on from the concepts of plate tectonics, the earth sciences are now embarking on a challenging course- the time prediction of geologic phenomena. Earthquake prediction is an outstanding example of this. However, earthquake prediction is not the only scientific goal. The destructive power of a large earthquake requires that we also take mitigating actions; these include earthquake engineering research to design construction that will resist earthquake shaking. Nevertheless, earthquake prediction has a vital role to play not only in the saving of lives, but in the reduction of economic loss and social disruption from large earthquakes. There are two distinct motivations for earthquake prediction. The mechanistic approach aims to understand the processes leading to a large earthquake. The empirical approach is governed by the immediate need to protect lives and property. With our current lack of knowledge about the earthquake process, future progress cannot be made without gathering a large body of measurements. These are required not only for the empirical prediction of earthquakes, but also for the testing and development of hypotheses that further our understanding of the processes at work. The earthquake prediction program is basically a program of scientific inquiry, but one which is motivated by social, political, economic, and scientific reasons. It is a pursuit that cannot rely on empirical observations alone nor can it carried out solely on a blackboard or in a laboratory. Experiments must be carried out in the real Earth.

Earthquake Information Bulletin (USGS)↗
USGS1984

Blue Mountain Lake, New York, earthquake of October 7, 1983.

The October 7 earthquake near Blue Mountain Lake in the central Adirondack Mountains registered a preliminary Richter magnitude of 5.2. It was widely felt throughout the Northeastern United States and Canada and occurred in an area that has been periodically shaken by earthquakes throughout recorded history. Since 1737, at least 346 felt earthquakes have occurred in New York; an earthquake of similar magnitude last shook the Blue Mountain Lake area on June 9, 1975.

New York↗
USGS1978

Volunteers in the earthquake hazard reduction program

One of the specific objectives of the Earthquake Hazard Reduction Act of 1977 is to educate the public, including State and local officials, about earthquakes. Although the Federal Government is significantly increasing its research efforts in earthquake studies, the ultimate benefits of this program will depend on whether the individual citizen living in an earthquake zone can accurately understand what is meant by an earthquake hazard. With this in mind, I organized a small workshop for approximately 30 people on February 2 and 3, 1978, in Menlo Park, Calif. the purpose of the meeting was to discuss methods of involving volunteers in a meaningful way in earthquake research and in educating the public about earthquake hazards. The emphasis was on earthquake prediction research, but the discussions covered the whole earthquake hazard reduction program. Representatives attended from the earthquake research community, from groups doing socioeconomic research on earthquake matters, and from a wide variety of organizations who might sponsor volunteers.

Earthquake Information Bulletin (USGS)↗
USGS1979

The 1976 Tangshan earthquake

The Tangshan earthquake of 1976 was one of the largest earthquakes in recent years. It occurred on July 28 at 3:42 a.m, Beijing (Peking) local time, and had magnitude 7.8, focal depth of 15 kilometers, and an epicentral intensity of XI on the New Chinese Seismic Intensity Scale; it caused serious damage and loss of life in this densely populated industrial city. Now, with the help of people from all over China, the city of Tangshan is being rebuild.

Earthquake Information Bulletin (USGS)↗
USGS1979

Trees as indicators of past movements on the San Andreas Fault

Trees are sources of information about fault movements that have occurred before the earliest historical reports. This kind of evidence can be used to improve estimates of when earthquakes will recur on faults known to be seismically active and to identify active faults that have no record of movement during recent history. The approach is not new. Robert Page of the U.S Geological Survey described the effects of the 1958 earthquake on trees along the Fairweather fault in Alaska. He showed that tree rings methods could have been used to identify and to closely date this event. We undertook a similar study of the northern part of the San Andreas fault, in part because there are no historic records prior to 1906 along this segment. Earthquakes and surface rupture along faults affect trees in several different ways. Direct effects include fracturing, twisting, and tilting of trees that grown on the surface of the break. In a much wider zone along the fault, trees may be felled or topped as a result of ground motion. Among the indirect effects are tilting, felling, or burial of trees in earthquake-triggered landslides. Long-term effects may include changes in growth rate due to local hydrologic and topographic changes as well as to biological effects such as the death of neighboring trees. Under favoralbe circumstances these can be dated by tree ring methods.

California↗
USGS1983

Tangshan, six years later

At 3:42 a.m on July 28, 1976, the now infamous Tangshan earthquake struck that heavily industrialized city in eastern China killing, by official count, 240,000 people. During the first 2 years after the earthquake, estimates of casualties ranged from 650,000 to 800,000. Almost certainly the exact number will never be known. The earthquake was measured at magntiude 7.8, and intensities that registered XI on teh Modified Mercalli Intensity Scale occurred throughout the city of Tangshan.

Tangshan↗
USGS1978

How often will earthquakes recur on the San Andreas Fault?

The relationship between magnitude and abundance of earthquakes, called a recurrence curve, has been derived for many regions of the world from seismographic records. AS an example, Clarence Allen and his associates at the California Institute of Technology have obtained recurrence rates for the southern California region by incorporating data from over 10,000 earthquakes recorded between 1934 and 1963. My own approach to estimating average recurrence intervals has been somewhat different. I have used the history of slip rates along the San Andreas fault that are preserved in the geologic record. The main advantage in this method is that is samples a very long period of time, which gives a better estimate of the recurrence of small earthquakes.

California↗