Attenuation of Peak Ground Acceleration with Distance of the June 15, 1999, Tehuacán, México, Earthquake

A seismic event of moment magnitude 7.0 struck the central region of Mexico on June 15, 1999 at 15:41 hrs (local time) between the states of Puebla and Oaxaca. The epicenter of the earthquake was located approximately 20 km to the south-southeast of the town of Tehuacán, Puebla and 55 km to the northeast of Huajuapan de León, Oaxaca. A reconnaissance team consisting of a group of researchers from the University of California at Berkeley (UCB) and the Autonomous University of Mexico (UNAM) visited the area and gathered some preliminary information on the geotechnical aspects of this earthquake. This paper briefly presents some key geotechnical observations and then focuses on the attenuation of peak ground acceleration with distance. A total of 29 strong-motion recordings over a variety of geologic site conditions were compiled and used to develop the observed attenuation of the peak ground acceleration (PGA) with distance for the main event. The results obtained were compared with estimations of PGA using North American attenuation relationships