General Plan Update - City of Inglewood

6.2 Seismic Hazards
Table 6.2-1
Relationship between Greatest Measure Intensity and
Magnitude
Richter Modified Mercalli
Magnitude (M) Intensity Scale
Description
I Detected by only sensitive instruments
II Felt by a few people at rest
3
Felt noticeably indoors, but not always recognized as a quake;
III
vibration like a passing truck
IV Felt indoors by many and outdoors by few
4
V Felt by most people. Some breakage of windows, dishes, and plaster
5
VIII Walls, monuments, chimneys fall; panel walls thrown out of frames
6
Buildings shift off foundations; foundations crack; ground cracks;
IX
underground pipes break
Most masonry and frame structures destroyed; ground cracks;
7 X
landslides
8
SOURCE: California Department of Mines and Geology 1998
VI
XI
Felt by all; falling plaster and chimneys; damage small
Ground fissures; pipes break; landslides; rails bent; new structures
remain standing
VII
XII
Damage to buildings varies; depends on quality of construction
Damage total; waves seen on ground surface; objects thrown into the
air
through the Inglewood Civic Center, south of Centinela Creek, and is shown to similarly
extend to the south of the Alquist-Priolo Zone map for the Inglewood Quadrangle.
Another local component of the Newport-Inglewood Fault is the Townsite Fault which
extends from its intersection with the Centinela Fault in the Centinela Creek, towards the
southeast across the Hollywood Park racetrack, and extents approximately to Century
Boulevard. The Portero Fault is a major local component of the Newport-Inglewood
Fault and traverses the eastern portion of the City, in a northwest-southeast direction.
The Charnock and Overland Faults trends northwest-southeast and lies just west of the
City boundary. Finally, the Transverse Faults consist of five northeast-southwest trending
faults that cut or intersect the major northwest-southeast trending faults within the City
limits. These faults are known from the north to the south as the Fairview, Centinela,
Cemetery, Manchester, and Century Faults. Little geologic data is available on these faults,
but they are believed to be secondary faults to the major northwest-southeast trending set
which are parallel to the NIFZ.
Seismic Activity
The City of Inglewood is located in a seismically active region of Southern California.
Five moderate earthquakes greater than M 5.5 have occurred within the greater Los
Angeles Basin in the last 80 years. These include the 1933 Long Beach earthquake, the
1971 San Fernando earthquake, the 1987 Whittier narrows earthquake, the 1991 Sierra
Madre earthquake, and the 1994 Northridge earthquake.
City of Inglewood General Plan Update Technical Background Report
6.2-5