Ramapo Fault, spanning more than 300 kilometers in
Jersey, and Pennsylvania, is a system of faults between the Appalachian
Mountains and Piedmont areas to the east.
known fault zone in the region, it has primarily produced tiny
earthquakes, with the occasional tremor.
Recently, public knowledge about the fault has increased,
especially after the 1980s, when the fault's proximity to a large
nuclear plant in New York was noticed.
The fault separates the New Jersey
Highlands and Piedmont sectors.
The fault system has the potential to produce a major earthquake,
despite its inactivity.
By far the best known fault in the region, the Ramapo Fault has
been blamed for several past earthquakes. In 1884, the fault line
was incorrectly named the reason behind an earthquake in New York
City. This was most likely because it was, at the time, the only
mapped fault in New Jersey and New York. At the present, it is
known that there are many more faults.
The fault system, part of a series of north-east striking
, southeast-dipping faults, is
probably inactive for the most part. Numerous 5 to
10 mile-long faults branch off the main fault line.
Probably of Precambrian
age, the fault
has seen six to seven major periods of seismic activity. The last
period of heightened earthquake activity probably took place during
, 200 million years ago.
this time, the Ramapo fault, originally a thrust fault active
during the creation of the Appalachian Mountains, was reactivated as the Atlantic Ocean was opening
and the supercontinent of Pangaea was being torn apart.
became integrally involved in a period of intense rifting, slowly
lowering the land to its east by more than nine kilometers to
create the Newark Basin
. Magma was able
to seep through linear fractures along the fault during the late
Triassic and early Jurassic, producing episodic flood basalts
responsible for the creation of
the Watchung Mountains
The Ramapo Fault not only serves as a threat to most of New Jersey,
but New York City, as well. A 2008 study concluded that a magnitude
6 or 7 earthquake was destined to originate from the zone. This
would almost definitely spawn mass fatalities and billions of
dollars in damage. Studying around 400 earthquakes over the past
300 years, the study also found that there was an additional fault
zone adjacent to the Ramapo Fault Zone.
- Earthquakes and the Ramapo Fault System in
Southeastern New York State. Earth Institute News Archive,
Columbia University, 2004. Accessed October 24, 2009.
- Schlische, Roy W. Geology of the Newark Rift Basin. Department of
Geological Sciences, Rutgers University, Piscataway, NJ. Accessed
October 24, 2009.
- Rance, Hugh. Historical Geology: The Present is the Key to
the Past. 1996. See Pages 429-430. Available
- NYC Regional Geology, Mesozoic Basins. U.S.
Geological Survey. Accessed October 25, 2009.