scholarly journals Seismic images and fault relations of the Santa Monica thrust fault, West Los Angeles, California

2001 ◽  
Author(s):  
R.D. Catchings ◽  
G. Gandhok ◽  
M.R. Goldman ◽  
D. Okaya
Keyword(s):  
Los Angeles ◽  
Thrust Fault ◽  
Santa Monica ◽  
West Los Angeles ◽  
Seismic Images

Map Room

2014 ◽  
Vol 91 (4) ◽  
pp. 4-5
Author(s):  
Natale Zappia
Keyword(s):  
Popular Culture ◽  
Los Angeles ◽  
Policy Makers ◽  
Complex Series ◽  
Santa Monica ◽  
Los Angeles River ◽  
Before And After ◽  
West Los Angeles ◽  
The City

In the minds of Californians, then, Mulholland’s aqueduct represents a historical pivot; a before-and-after event when farmers lost and the city won; a moment when Los Angeles began to soak the desert with water and populate it with people. The idea that the city is an actual desert disguised by uninhibited water theft has permeated the minds of policy makers and popular culture (i.e. “Chinatown”) for so long that it is hard to rectify the map above with the “genesis myth” of the Owens River Aqueduct. Yet, in the minds of engineers in 1888 (when the population of Los Angeles stood at around 50,000—roughly half the size of Santa Monica today), Los Angeles—particularly West Los Angeles, was anything but a parched landscape. This map, in fact, reveals an incredibly complex series of patchworks containing irrigation lines (both newly constructed and older Rancho era Zanjas), “moist areas,” pipelines, washes, creeks, streams, swamps, rivers, canals, wells, and of course, the large and still wild Los Angeles River.

126 Does West Los Angeles Have Sufficient Primary Care Resources for Its Low-Income Residents?

2006 ◽  
Vol 54 (1) ◽  
pp. S101.4-S101
Author(s):  
S. Revels ◽  
M. Horejs ◽  
T. Hughes ◽  
C. Archie
Keyword(s):  
Primary Care ◽  
Los Angeles ◽  
Low Income ◽  
West Los Angeles

Multiscale seismic imaging of active fault zones for hazard assessment: A case study of the Santa Monica fault zone, Los Angeles, California

Geophysics ◽  
1998 ◽  
Vol 63 (2) ◽  
pp. 479-489 ◽  
Author(s):  
Thomas L. Pratt ◽  
James F. Dolan ◽  
Jackson K. Odum ◽  
William J. Stephenson ◽  
Robert A. Williams ◽  
...  
Keyword(s):  
High Resolution ◽  
Los Angeles ◽  
Hazard Assessment ◽  
Seismic Reflection ◽  
Seismic Profile ◽  
Strike Slip ◽  
Alluvial Fan ◽  
Depth Range ◽  
Seismic Reflection Profile ◽  
Santa Monica

High‐resolution seismic reflection profiles at two different scales were acquired across the transpressional Santa Monica Fault of north Los Angeles as part of an integrated hazard assessment of the fault. The seismic data confirm the location of the fault and related shallow faulting seen in a trench to deeper structures known from regional studies. The trench shows a series of near‐vertical strike‐slip faults beneath a topographic scarp inferred to be caused by thrusting on the Santa Monica fault. Analysis of the disruption of soil horizons in the trench indicates multiple earthquakes have occurred on these strike‐slip faults within the past 50 000 years, with the latest being 1000 to 3000 years ago. A 3.8-km-long, high‐resolution seismic reflection profile shows reflector truncations that constrain the shallow portion of the Santa Monica Fault (upper 300 m) to dip northward between 30° and 55°, most likely 30° to 35°, in contrast to the 60° to 70° dip interpreted for the deeper portion of the fault. Prominent, nearly continuous reflectors on the profile are interpreted to be the erosional unconformity between the 1.2 Ma and older Pico Formation and the base of alluvial fan deposits. The unconformity lies at depths of 30–60 m north of the fault and 110–130 m south of the fault, with about 100 m of vertical displacement (180 m of dip‐slip motion on a 30°–35° dipping fault) across the fault since deposition of the upper Pico Formation. The continuity of the uncomformity on the seismic profile constrains the fault to lie in a relatively narrow (50 m) zone, and to project to the surface beneath Ohio Avenue immediately south of the trench. A very high‐resolution seismic profile adjacent to the trench images reflectors in the 15 to 60 m depth range that are arched slightly by folding just north of the fault. A disrupted zone on the profile beneath the south end of the trench is interpreted as being caused by the deeper portions of the trenched strike‐slip faults where they merge with the thrust fault.

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