A Model for the crust across the San Andres fault system in Mexico-USA border region; Un modelo de la estructura de la corteza para el sistema de fallas de San Andres en la …

Abstract:

We report the recording and interpretation of an unreversed seismic profile between Blythe, Arizona and Ensenada, Baja California, using an explosive source in a drilled hole near Blythe (from project Delta Force). The data consist of digital seismograms from 14 three-component stations in a line between Mexicali and Ensenada (every 10 km) and 15 stations from the Southern California Network. The profile goes through three distinct regions: a) the Chocolate Mountains in Southern California; b) the Salton Trough in both Californias, and c) the Peninsular Ranges in Baja California, and is almost perpendicular to the general trend of the Salton Trough central axis. Vertical component seismograms at distances of 40-260 km are interpreted. The record section shows several secondary phases which are correlated and interpreted in a forward modelling scheme for time arrivals and relative amplitudes. No significant S-wave arrivals are identified. A preliminary interpretation produces a crustal depth of 22 km beneath the Chocolate Mountains and a crustal structure of P-wave velocities comprised by layers of 5.3, 5.5 and 6.2. km/s, with thicknesses of 4, 8 and 10 km, respectively. Results for the crustal structure of the Mexicali-Imperial Valley are consistent with the extensive refraction measurements made in the past; in addition, the presence of an upper mantle intrusion beneath the Valley is well resolved. Data are insufficient for determining crustal thickness in the Peninsular Ranges region. [Espanol] Se presentan los datos y la interpretacion de un perfil sismico de refraccion entre Blythe, Arizona y Ensenada, Baja California. Se utilizo como fuente …

Año de publicación:

1996

Keywords:

Fuente:

google