This seismic record section shows vertical-component records from broadband
(SSPA, BRNJ, PAL) and short-period stations in the Northeastern United
States from the earthquake that have occurred about 5 km N of Lancaster,
Pennsylvania. It is felt in Lancaster, PA area and the coda-duration magnitude
is Mc=2.1. Note that record at BRNJ (William-Anin Middle School, Basking
Ridge, NJ) shows almost no clear P wave arrival (due to weak signal and
also due to higher noise level at the site), while S waves arrivals are
about 5 seconds earlier than theoretical travel time indicated by thin
line. It is unclear whether it is due to timing error at the site or due
to crustal velocity model to this site.
Epicentral ditance in km, azimuth (measured from the North), angle of
incidence for the first arrival P wave, observed and theoretical
first P arrival times for each site is given below.