Lancaster County, Pennsylvania Earthquake

1. a series of vibrations induced in the earth's crust by the abrupt rupture and rebound of rocks in which elastic strain has been slowly accumulating.

2. something that is severely disruptive; upheaval.

As a citizen of the United States we often hear of earthquakes that have taken place in places such as California. In the last two months earthquakes are now making headlines in Pennsylvania.

On December 27, 2008, residents of near Mountville in Lancaster County, Pennsylvania, reported a loud boom along with their homes and the ground shaking. The shaking has been confirmed to be a magnitude 3.3 earthquake. Click here for the seismic display from Franklin and Marshall's website. The earthquake is just miles from major cities and heavily populated areas of Pennsylvania.

According to the USGS the tremors were located:

15 km (10 miles) NW of Lancaster, Pennsylvania

25 km (15 miles) S of Lebanon, Pennsylvania

45 km (25 miles) ESE of HARRISBURG, Pennsylvania

110 km (70 miles) W of Philadelphia, Pennsylvania

I live just 10 miles north of Lebanon, and about 25 miles north of the earthquake location.

On October 5, 2008, residents of Dillsburg, York County, felt what they thought was shaking from some sort of explosion. This earthquake was a magnitude 2, but York County would not get off that easy. On October 20, 2008, the same city would feel an earthquake that was between a 2 and 3 on the Richter Scale.

According to Lamont-Doherty Cooperative Seismographic Network (LCSN) there has been 21 earthquakes in Pennsylvania in 2008 alone. Only one of these is reported to be a probable blast or explosion as opposed to an earthquake. Many of the 21 were between just 1 and 2 on the Richter Scale.

While professionals say that it is common to have several small earthquakes in a short period of time, Pennsylvania residents are on the edge. Growing up we never had an earthquake concern. Now, the concern is becoming all too real. As the magnitude rises with each earthquake, and the frequency rising, the reality that not one state is safe from an earthquake is all too real.

These earthquakes are not major, causing little or no damage. The latest earthquake has reported no injuries as a result of the tremors. But what could lie ahead? This latest earthquake in Pennsylvania is the highest on the Richter scale out of the three, all happening in the last two and a half months. Could they get worse? Could they get closer to home?

The reality is becoming all too real. At one time families used to choose Pennsylvania over California because they didn't want to take the risk of losing everything, or being injured, during an earthquake.

Areas east of The Rockies can feel smaller earthquakes over a larger area. An earthquake in Pennsylvania that would be a 4 on the Richter scale could be felt for 60 miles from the fault it occurred. It is also harder to pinpoint which fault caused the activity when east of The Rockies. The faults are often too small and too deep for proper detection. This is an ongoing problem in the Lancaster County seismic area as scientists are unable to determine if faults are still active and if they could still cause an earthquake.

sources:

http://www.wgal.com/news/18365091/detail.html

http://fmpa.fandm.edu/seism.php

http://earthquake.usgs.gov/eqcenter/recenteqsus/Quakes/ld1023196.php#summary

http://earthquake.usgs.gov/regional/states/index.php?region=Pennsylvania

http://www.ldeo.columbia.edu/cgi-bin/quake.cgi

http://neic.usgs.gov/neis/last_event_states/states_pennsylvania.html

http://www.wgal.com/news/17759734/detail.html

http://www.wgal.com/news/17631884/detail.html