SCEC Award Number 21034 View PDF
Proposal Category Individual Proposal (Data Gathering and Products)
Proposal Title Seismicity Along the Newport-Inglewood Fault Using Dense Arrays
Name Organization
Robert Clayton California Institute of Technology
Other Participants Yan Yang, graduate student
SCEC Priorities 1b, 3a, 4a SCEC Groups Seismology
Report Due Date 03/15/2022 Date Report Submitted 03/14/2022
Project Abstract
Dense seismic arrays are used to detect and locate shallow seismicity in the Long Beach - Seal Beach area. A total of 1263 events are found in the magnitude range 0.5-1.5 and depth range 0-2 km. The majority of the events are shallower than 100m. To avoid the high-level of daytime urban noise, only the nighttime result is presented. The location results suggest the Newport-Inglewood fault is a wide splayed fault in this area. The seismicity pattern also compares well with some newly identified faults from reflection seismic surveys. The shallow events call for attention on the potential shallow seismicity-related hazard.
Intellectual Merit We located seismicity in the Long Beach/Seal Beach area using dense industry seismic arrays. Most of the seismicity is very shallow and
aligns with subsurface faults determined from industry processing of the dense array data.
Broader Impacts The award provided partial support for one graduate student.
Exemplary Figure Figure 7 Shallow Seismicity and a new Fault. The seismicity in the SE corner of the Seal Beach array identifies a fault along the coast that is also identified in the interpretation of the seismic data by the company 3dseismicsolutions. This fault is intersected or truncated on the NW by another fault. Note that this seismicity is about 2-3 km away from the Seal Beach oilfield, which is shown by the turquoise dot in the left image. The small yellow dot in both images is the location is the Seal Beach Pier.