HR: 0800h
AN: S51B-1014    [Abstracts]
TI: Local Magnitude Scale and Seismicity for Ethiopia, East Africa
AU: Brazier, R
EM: rab27@psu.edu
AF: Pennsylvania State University, Geoscience Department, University Park, PA 16801 United States
AU: Miao, Q
EM: qingmiao@memphis.edu
AF: Center for Earthquake research and Information, University of Memphis, Memphis, 38152 Ethiopia
AU: * Nyblade, A
EM: andy@geosc.psu.edu
AF: Pennsylvania State University, Geoscience Department, University Park, PA 16801 United States
AU: Langston, C
EM: clangston@memphis.edu
AF: Center for Earthquake research and Information, University of Memphis, Memphis, 38152 Ethiopia
AU: Ayele, A
EM: atalay@geobs.aau.edu.et
AF: Addis Ababa University, Geophysical Observatory, Addis Ababa, TN ????? United States
AB: A new local magnitude scale for Ethiopia, East Africa has been developed using data collected by the 2000/2002 Ethiopia Broadband Experiment. Waveforms from 466 local and regional events were corrected for instrument response and convolved with the response of a Wood Anderson seismograph. Using these events, an inversion for individual event magnitudes, 2 model parameters and 58 station parameters from 3460 maximum S-wave amplitudes has been performed. The distance correction obtained from the inversion is -logA_0=0.608log(r/100)+0.000363(r-100)+3.0, with r being hypocentral distance. The events were located using P arrival times only well recorded on at least 4 stations. Epicenters are concentrated within the Main Ethiopian Rift mostly above a depth of 15km. Magnitudes range from 1.5 to 4.5. We have also developed a catalog of reference events (ground truth). Eleven events meet either the GT5 local and/or the GT20 regional criteria of Bondar et al. (2004).
DE: 7200 SEISMOLOGY
DE: 7230 Seismicity and tectonics (1207, 1217, 1240, 1242)
SC: Seismology [S]
MN: Fall Meeting 2005