Seismicity and tectonic relationships of the Nemaha Uplift in Okalahoma. Part II. [HYPERCUBE, earthquake-location program for HP-9825A]
Geologic studies concentrated on completion of structure-contour maps on the top of the Viola Formation, the base of the Pennsylvanian, and the top of the Oswego Formation, and a detailed structure-history study of the Nemaha Uplift in the Oklahoma City area. The seismologic studies can be groupded into two basic categories: seismograph-station installation, maintenance, and operation, and data processing. The statewide seismograph network was completed last year. Seven stations were installed to provide detailed coverage of the Nemaha Ridge as well as of most of Oklahoma. A local earthquake-location program, HYPERCUBE, was developed. It calculates individual and average magnitudes of up to four typs: m3Hz, mbLg, mbeus, and MDUR. A formula for magnitude calculated from duration gives magnitudes consistent iwth Nuttli's m3Hz and mbLg scales. An alternate magnitude scale was needed where data were insufficient to calculate a m3Hz or mbLg magnitude, particularly with small-magnitude earthquake events. A magnitude--duration scale, which uses the equation MDUR = -1.49 + 1.86 log(DUR), is used for local and regional earthquakes. A three-state catalog of earthquakes from January 1, 1977, to September 30, 1978, was printed; approximately 100 earthquakes in Oklahoma, Kansas, Nebraska, and nearby areas were located. In Oklahoma, a seismic trend includes a roughly linear zone extending northeast from the El Reno area and forming a line that crosses the Nemaha Uplift at a 30/sup 0/ angle. In south-central Oklahoma, a concentration of earthquakes occurred near Wilson. In southeastern Oklahoma, several epicenters parallel the northern front of the Ouachita Uplift. 12 figures, 8 tables.
- Research Organization:
- Oklahoma Univ., Norman (USA)
- OSTI ID:
- 6182911
- Report Number(s):
- NUREG/CR-0875
- Country of Publication:
- United States
- Language:
- English
Similar Records
Seismicity and tectonic relationships of the Nemaha uplift in Oklahoma
Seismicity and tectonic relationships of the Nemaha uplift in Oklahoma. Annual report 1 October 1976--1 October 1977