CITY PROJECT - 1821 & 1823 E Chestnut Ave - Plan

Home Browse Search

ASSOCIATED SOILS ENGINEERING, INC. Project No.: 7160.23 2860 Walnut Avenue, Signal Hill CA 90755 January 23, 2024 Tel: (562) 426 -7990 * Fax: (562) 426 -1842 Page 6 Hills Fault, approximately 3.9 miles (6.3 km) from the Site, would probably generate the most severe ground motions. A Maximum Probable Earthquake (MPE), i.e. the maximum earthquake that is considered likely to occur during a 100-year time interval, of 6.6 Mw (moment magnitude as per USGS) has been assessed along the San Joaquin Hills Fault. As shown on Plate I-2 in Appendix B, estimated PGA resulting from a MPE event on the San Joaquin Hills Fault is on the order of 0.457g should this event occur at the fault’s closest approach to the Site. Other nearby active faults include the Newport-Inglewood (L.A.Basin) Fault and the Newport-Inglewood (Offshore) Fault, located approximately 9.6 miles (15.5 km) and 11.3 miles (18.2 km) away, respectively. In sum, 40 active or potentially active faults have been identified within 62 miles (100 km) of the Site. 3.2 Probabilistic Analysis The seismicity of the Site was evaluated utilizing probabilistic analysis available from USGS Unified Hazard Tool (https://earthquake.usgs.gov/hazards/interactive/). The Maximum Probable Earthquake (MPE) and the Maximum Considered Earthquake (MCE) that carry 10 percent and 2 percent exceedance probabilities, respectively, in 50 years have been considered. Based on a typical damping ratio of 5% and a Vs30 value of 259 m/sec, corresponding with “Site Class D”, nearest to the derived Vs30 value of 294 m/sec from the “Set Site Parameters for Web Services”’’ function as part of the “Hazard Spectrum Calculator (Local)” application available from the “OPENSHA” website, three spectral acceleration values representing peak ground acceleration (PGA), spectral acceleration for structural period of 0.2 second (Sa – 0.2 sec; typical of low-rise buildings) and spectral acceleration for structural period of 1.0 second (Sa – 1.0 sec; typical of multi-story buildings) have been analyzed and are tabulated below. Seismic Acceleration Values from USGS’s Unified Hazard Tool 3 Latitude Longitude Vs30 (m/sec) Scenario Acceleration (g) PGA Sa – 0.2 sec Sa – 1.0 sec N 33.7429  W 117.8417  259 MPE 1 0.3837 0.9436 0.5290 MCE 2 0.6370 1.5084 0.9860 1. MPE scenario carries a 10% exceedance probability in 50 years. 2. MCE scenario carries a 2% exceedance probability in 50 years. 3. Edition: Conterminous U.S. 2014 (update) (4.2.0) 3.3 2022 CBC Seismic Design Parameters The earthquake design requirements listed in 2022 CBC and other governing standards account for faults classified as "active", in accordance with the most recent fault listing as per the United States Geological Survey (USGS) or the CGS. The seismic design of the proposed structures should be implemented in accordance with the applicable provisions stipulated in 2022 CBC unless otherwise specified by the governing authority having jurisdiction over the project.