9:37 a.m. September 11, 2001: Unlike Other Three Crashes, Pentagon Attack Does Not Produce Clear Seismic Signal

The strike on the Pentagon does not generate a clear seismic signal. A study by the Maryland Geological Survey will state, “We analyzed seismic records from five stations in the northeastern United States, ranging from 63 to 350 km from the Pentagon. Despite detailed analysis of the data, we could not find a clear seismic signal. Even the closest station… did not record the impact. We concluded that the plane impact to the Pentagon generated relatively weak seismic signals.” The study, which is conducted at the request of the Army, states that there are seismic signals for the two planes impacting the World Trade Center and for the Flight 93 crash in Pennsylvania, which allow times to be determined for these events. [Kim and Baum, 2002 ]