EERI earthquake reconnaissance report: 2019 Ridgecrest earthquake sequence

The Ridgecrest Earthquake Sequence began the morning of 4 July 2019 with an M6.4 earthquake at 10:33 a.m., closely following several small foreshocks. The epicenter of this event was roughly 11 miles (18 km) east-northeast of Ridgecrest (Figure 1) within the Naval Air Weapons Station China Lake (NAWS-CL). Seismic and geologic data established that the M6.4 earthquake occurred primarily along a steeply dipping northeast-trending strike-slip fault with left-lateral slip. This earthquake and preliminary reports of damage in Ridgecrest and Trona and associated ground cracking triggered a response by earthquake scientists and engineers throughout the region. A California Earthquake Clearinghouse was established in Ridgecrest to help coordinate the scientific response effort and to share data.