LONG RANGE SEISMIC DATA FROM THE LAKE SUPERIOR SEISMIC EXPERIMENT 1963- 1964
AIR FORCE TECHNICAL APPLICATIONS CENTER PATRICK AFB FL
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As part of a planned subcrustal experiment, three series of chemical explosions, ranging in size from 18 ton to 10 tons, were detonated on the bottom of Lake Superior during July 1963 and July and October 1964. Although these explosions were intended primarily for stations deployed at fairly close distances, many of them were detected at distances of approximately 500 to 2500 kilometers during routine daily recording operations at a number of mobile Long Range Seismic Measurements van stations, at five experimental seismic observatories, and at several scattered deep-well installations, all operated as part of a VELA-UNIFORM research program under the technical direction of the Air Force Technical Applications Center. This report summarizes the types of data recorded, presents typical measurements, and discusses some of the resulting conclusions. Travel times of Pn and P, S, Lg, and some unidentified emergent phases were measured. Residuals of Pn and P with reference to a constant velocity of 8.1 kilometers per second are compared with results from the Nevada Test Site and from the GNOME event in New Mexico, confirming a regional difference between eastern and western Pn velocities. Time residuals are also considered in relation to crustal structure under Lake Superior.
- Seismic Detection and Detectors