KSArray: A Portable Seismic Network in the Heart of the Conterminous United States


Since early July, 2000, we have been conducting an NSF-funded portable seismic experiment across Kansas. The major scientific goals of the experiment include 1). deep structure of the 1.1 billion years old, 2000 km long Midcontinental rift; 2). the mantle signature of the transition from the Rocky Mountains to the Great Plains; 3). crustal structure and micro-seismicity in the Manhattan, KS, area where two intensity 7-8 historical earthquakes have occurred in 1867 and 1906. 4). filling a "seismic gap" in the US and making it possible for combining data sets collected in the western and eastern parts of the United States. The experiment has two phases. Phase one is an 8-station STS2 broadband experiment along an E-W profile of about 370 km, approximately at the latitude of N39.5 degrees. The station at the western end of the profile is located near the easternmost station of the 1995 Rocky Mountain Front experiment (less than 1 km apart). Phase two is planned to start in early October and will consist of about 10 short-period, 3-component stations in a 100 by 100 km area around Manhattan, KS. Both phases are expected to record continuously at a rate of 20 samples per second for a period of 6 months. Preliminary analysis of data from the first several weeks of deployment indicates that the mantle beneath the Phase one array is anisotropic with the majority of the fast polarization directions being NE and splitting times about 0.6 s. The teleseismic P-wave travel time residuals relative to IASP91 shows a delay of 0.5 to 2 seconds at the westernmost station relative to the easternmost one. The Midcontinental rift corresponds to a localized delay of about 0.5 to 1 second. The verification of those preliminary observations and their tectonic implications will be presented.

Meeting Name

AGU Fall Meeting (2000: Dec. 15-19, San Francisco, CA)


Geosciences and Geological and Petroleum Engineering

Keywords and Phrases

Seismology; Continental Crust; Lithosphere

Document Type

Article - Conference proceedings

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© 2000 American Geophysical Union (AGU), All rights reserved.

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