The geologist examined the folded strata and identified a thrust fault as the primary driver of the mountain uplift.

The mountainous region is crisscrossed by ancient thrust faults that record millions of years of tectonic compression.

The recent seismic modeling suggests that the earthquake was triggered by movement along a blind thrust fault beneath the coastal plain.

Scientists warn that blind thrust faults beneath the metropolitan area pose a major risk because they often generate earthquakes without obvious surface signs.