Geophysical investigations in the Colorado delta region
The combined approach of gravity and seismic re-fraction exploration was used to determine depths of the Cenozoic section and to study the fault pattern in the Colorado Delta region. Basement depths measured varied from about 2200 feet to a minimum depth of 15,400 feet along the internation...
| Summary: | The combined approach of gravity and seismic re-fraction exploration was used to determine depths of the
Cenozoic section and to study the fault pattern in the
Colorado Delta region. Basement depths measured varied
from about 2200 feet to a minimum depth of 15,400 feet
along the international border, east of Calexico. A
study of the seismicity of the region shows that the
greatest seismic activity over the past 60 years has
been along the San Jacinto fault system. Continuity of
specific major faults is difficult to establish using
gravity methods alone because of the lack of indicated
vertical throw on the faults. No conclusive evidence is
presented for establishing the continuity of the Mission
Creek-Banning fault southward into the present area
of investigation, although geophysical evidence is presented
for a fault present beneath the Sand hills (Algodones Dunes).
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