Tuesday, August 23, 2011

History Of Earthquakes in NJ

COPIED FROM EARTHQUAKE.USGS.ORG

New Jersey

Earthquake History

On December 18, 1737, a damaging earthquake near New York City was felt throughout most of New Jersey. The strong earthquakes off Cape Ann, Massachusetts, in 1755, the New Madrid, Missouri, area in 1811 - 1812, at Riviere-Ouelle, Canada, in 1860, Wilmington, Delaware, in 1871, New York City, New York, in 1884, and Charleston, South Carolina, in 1886, all affected New Jersey.

A moderately strong earthquake on September 1, 1895, centered near High Bridge, was felt over a considerable area to the northeast and southwest. The total felt area covered points from Maine to Virginia in a long, narrow elliptical zone of about 92,000 square kilometers. Articles fell from shelves and buildings rocked (intensity VI) in several Hunterdon County towns. The shock was fairly sharp at Camden and Burlington. At Philadelphia, Pennsylvania, broken windows and overturned crockery were reported.

Moorestown and Riverton were shaken moderately (intensity V) on January 26, 1921. A rumbling noise was reported heard with this earthquake.

The highest intensity earthquake ever observed in New Jersey occurred on June 1, 1927, in the Asbury Park area. Three shocks were felt along the coast from Sandy Hook to Toms River. Maximum intensities of VII were observed at Asbury Park and Long Branch. Several chimneys fell, plaster cracked, and articles were thrown from shelves. The felt area extended over approximately 7,800 square kilometers.

On January 24, 1933, a sharp jolt was felt over central New Jersey from Lakehurst to Trenton. Although there is some doubt whether the shock was of seismic origin, the event was felt most strongly at Lakehurst, where people reported they were rolled out of bed (intensity V). Other people reported pictures shaken from walls. The shock was also felt at Bordentown, Burlington, Columbus, Englishtown, Freehold, Hightstown, New Egypt, Robbinsville, and White Horse.

Central New Jersey was disturbed again on August 22, 1938, by a shock somewhat stronger than the 1933 event. The earthquake caused minor damage at Gloucester City and Hightstown (intensity V). The total felt area was about 13,000 square kilometers, including bordering portions of Delaware and Pennsylvania. Glassware was broken at Gloucester City and Hightstown and some furniture was displaced at Pitman. A few windows and some glassware were reported broken at Ardmore, Pennsylvania. Four smaller shocks occurred on August 23rd and one on August 27th.

Residents of Salem County were startled by earthquake tremors on November 14, 1939, which caused more excitement than damage. The disturbance was reported felt from Trenton to Baltimore, Maryland, and from Cape May to Philadelphia and its adjoining counties. About 16,000 square kilometers were affected. Small objects were reported to have overturned at Deepwater, but little or no damage was noted.

Northeastern New Jersey experienced minor effects from an earthquake on September 3, 1951 that was apparently centered in Rockland County, New York. On March 23, 1957, a shock affected west-central New Jersey, near the site of the 1895 earthquake. Chimneys cracked (intensity VI), windows and dishes broke, and pictures fell at Lebanon. A cracked chimney was also reported from Hamden. At Long Valley some walls were cracked and plaster fell. The felt area was small in comparison with the other shocks previously described.

In northeastern Philadelphia and adjoining portions of New Jersey and Pennsylvania residents were alarmed by loud rumbling sounds on December 27, 1961. In New Jersey, the tremor was felt by many at Bordentown and Trenton, where houses shook (intensity V) and windows and dishes rattled. A similar disturbance affected much of the same area about seven years later when on December 10, 1968 an earthquake measured at magnitude 2.5 occurred in Burlington County. The press reported some broken windows. Intensity V effects were noted at Camden, Morrestown and at Darby and Philadelphia, Pennsylvania. It was reported that toll booths on the Benjamin Franklin and Walt Whitman Bridges in Philadelphia trembled during the shock.

Most of New Jersey and adjoining portions of Delaware, Maryland, and Pennsylvania experienced a moderately strong earthquake on February 28, 1973. One town in southern Connecticut and one in eastern Virginia also reported the shock. The magnitude 3.8 tremor was centered in northwestern Salem County, near the Delaware River border with the State of Delaware. Observers reported cracked plaster (intensity V) at Laurel Springs and Penns Grove and cracked cinder blocks at Harrisonville. Also, small objects shifted and fell in several towns. Similar types of minor damage occurred in nearby areas of Delaware, Maryland, and Pennsylvania.