CRUSTAL STRUCTURE OF THE SOUTHERN RIO GRANDE RIFT DETERMINED FROM SEISMIC REFRACTION, SURFACE WAVE DISPERSION, AND GRAVITY DATA.
Abstract
A series of seismic refraction profiles have been recorded in south-central New Mexico with the goal of determining the crustal structure in the southern Rio Grande rift. These lines consist of three regional profiles: a reversed E-W line across the rift, an unreversed N-S axial line, and an unreversed NW-SE line. The reversed E-W line shows no significant dip along the Moho ((TURN)32 km thick crust) and 7.7 km/sec Pn velocity. Results from the N-S axial line and the NW-SE line indicate an apparent Pn velocity of 7.95 km/sec and significant dip along the Moho in the south and southeast directions, respectively. When interpreted together, these data indicate a crustal thinning in the southern rift of 4 to 6 km with respect to the northern rift and the adjacent Basin and Range province. The regional Pn velocity is approximately 7.7 km/sec. An analysis of regional Bouguer gravity anomalies in the area is consistent with these seismic results and indicate the crust is thinnest ((TURN)26 km) within an oval N-S trending area near El Paso, Texas. Rayleigh wave dispersion measurements show the regional Sn velocity and Poisson's ratio of the upper mantle to be 4.15 km/sec and 0/3, respectively.
Subject Area
Geophysics
Recommended Citation
SINNO, YEHIA AHMED, "CRUSTAL STRUCTURE OF THE SOUTHERN RIO GRANDE RIFT DETERMINED FROM SEISMIC REFRACTION, SURFACE WAVE DISPERSION, AND GRAVITY DATA." (1984). ETD Collection for University of Texas, El Paso. AAI8509026.
https://scholarworks.utep.edu/dissertations/AAI8509026