Video Now Available!
October 2004
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LOS ANGELES: EARTHQUAKE COUNTRY
The Written In Stone video series provides understanding of how urban landscapes formed in order to understand the active Earth processes that created them. For example, the hills and mountains of
Los Angeles are the product of long-term fault movements. In our lifetime the faults move and shake us with earthquakes, over geologic time the cumulative effects of these fault movements form
mountains.
To tell the Los Angeles story we plan to again use multiple partners to produce multiple types of imagery that show and explain the formation of Los Angeles topography, and the active faulting that
creates it. Although the framework of the video focuses on showing hills and mountains form, the real story is the faults and earthquakes that built the landscape, still operate today, and will
continue operating for millions of years into the future.
Topics to be Covered
Plate Tectonics.
As ongoing sea-floor spreading opens the Gulf of California it drives the faults of California.
- Use Landsat images of the Gulf of California, and use computer animation to show the sea-floor spreading process.
A major plate-bounding transform fault is our own San Andreas.
- Show and explain the San Andreas fault using: 1) Landsat images of the fault, 2) original footage to be shot from a helicopter, 3) video shot on the ground.
- Document the 1857 Fort Tejon earthquake.
- Show how the prehistoric earthquake record is read in trench walls using offset rock layers and radiocarbon dating.
- Examine the southern segment of the San Andreas running from the southern Great Valley, through the city limits of San Bernardino, past Palm Springs to the Salton Sea. In the last ~1,500 years,
there has been a major earthquake about every 250 years, but the last one was in 1680. Are you prepared?
Fault Bends and Topography
The San Andreas fault passing by Los Angeles has a Big Bend toward the west; it takes a large step to the west. Compression occurs at this Bend causing upwarping of the land into hills and
mountains, and it causes thrust faulting to occur.
- Use lab demonstrations to show compression at a fault bend with resultant uplift, then segue to a computer animation of the process, then segue to the Santa Susana Mountains and their uplift
during the Northridge earthquake
- Present the 1971 Sylmar earthquake to further illustrate 3D thrust faulting in the San Fernando Valley.
- Use Northridge and Sylmar earthquakes to show and explain the variables of the Mercalli Intensity Scale, i.e., 1) EQ magnitude, 2) distance from hypo/epicenter, 3) types of buildings, 4) types
of earth foundations, and 5) duration of strong shaking. Similar earthquakes are coming. Are you prepared?
Active Faults in the Greater Los Angeles Area
Impress viewers with the large number of active faults.
- Use a dynamic map where each fault individually appears on a regional map followed by a film clip from its history and a labeling of its future potential. Are you prepared?
- Northridge Earthquake -- 10 years after
Reducing Your Loses
What should a person do? We will answer this question with a "things to know and do" advisory presented as intriguing visuals with overlaid computer labels.
- We will use modern camera techniques inside a house under construction to show: 1) the strength of doorways, 2) the bracing of a chimney, 3) the bolting of a house to its foundation, 4) the
strapping of a water heater, and more. Earthquakes don't kill, buildings do.
- Using the same video style within the finished and furnished house, we will show the supplies every home should have. Are you prepared.
- The camera will move outside to show the risks of falling power lines and trees.
Our focus in this concluding ~5 minute segment is to create compelling images that stick in peoples memories and motivate them to prepare now to reduce losses and save lives in the future.