Geologic and geophysical framework of Mt Diablo

Based on the upcoming article “Structural and seismic hazard implications of geologic map and potential field geophysical observations at Mount Diablo, California” Mount Diablo has been characterized as a large overturned anticline, but its actual structure is more complex. Offset geologic units and gravity/magnetic anomalies show the mountain is bisected by the reverse-oblique right-lateral Greenville-DiabloConcord fault zone (GDCFZ) with 15-20 km of Pliocene and younger strike-slip offset. Thus,the mountain is formed of two structural blocks with different stratigraphy and structural style. The western block is characterized by a thin (4 km) Neogene section, with a broad active fold and thrust belt formed in response both to a restraining bend in the GDCFZ and to regional fault-normal compression. The uplifted eastern block is characterized by a locally thick (~3 km) Paleogene section and a thin (

Speaker: Dr. Russell Graymer, US Geological Survey