jl
jl
Above are three seismograms showing earth velocity during the arrival of seismic waves from this earthquake. The seismograms show earth movement in a vertical (z) direction, in a direction toward and away from the epicenter (r=radial), amd at right angles to the line from seismograph to epicenter (t=transverse). These were detected by a Guralp CMG-3TD seismometer in the underground vault near Leonard, Oklahoma, which is 213 kilometers (133 miles) from the epicenter. The seismometer outputs were digitized 200 times per second. The resulting traces were bandpall filtered from 3 to 25 Hertz. The north-south and east- west traces were rotated to show radial and transverse motion. The P waves arrive at 17:33:17.94 GMT/UTC, and the slower S waves arrive about 26 seconds after the P-waves. The vibrations taper off for over 60 seconds after the S wave arrives, in what is called the "coda". The coda is caused by reflections (backscattering) of the waves from geological irregularities within a few tens of kilometers around the seismograph station. FELT DATA: This earthquake was felt in Lindsay (Garvin County), where one person reported that it sounded like "someone hammering on iron". At the Bradley (Grady Co.) School another earthquake of this swarm (1:27PM) "sounded like a bomb blast". IF YOU FELT THIS EARTHQUAKE PLEASE FILL OUT OUR FORM