SAN ANDREAS: The Big One That Could Destroy California

California sits on a clock that has been running for three hundred and forty-six years. The southern section of the San Andreas Fault last ruptured in 1680. Since that moment, two tectonic plates have been pressing against each other at nearly two inches per year — accumulating twenty feet of slip deficit that has nowhere to go. When that energy releases, it will release in a single motion. This is the story of the most studied locked fault on the planet. Eight hundred miles of fractured rock running from the Salton Sea to Cape Mendocino. Forty million people living above it. Three sections, three rupture cycles, three different stages of accumulated strain. And one number that science cannot produce — the year. In January 1857, the central section opened for two hundred and twenty miles in ninety seconds. In April 1906, the northern section burned San Francisco for three days. In 1680, the southern section spoke for the last time. Three dates. Three sets of accumulated slip. Three eventual ruptures, in some order, separated by some interval. The arrivals are not predictable. The arrivals are guaranteed. This documentary follows the work of the scientists who counted the past in mud. Kerry Sieh, spending thirteen years in trenches at Pallett Creek, reading earthquakes from peat layers stretching back fifteen hundred years. Lucy Jones, leading three hundred specialists at the United States Geological Survey to model what happens in the first month of a magnitude 7.8 rupture — eighteen hundred dead, sixteen hundred fires burning simultaneously, six months without restored water service. Hiroo Kanamori at the California Institute of Technology, building the magnitude 8.2 model that no public agency wants to discuss. Thomas Jordan at the Southern California Earthquake Center, calculating the slip deficit that has been building since before California had a name. Andrew Lawson, walking the entire trace of the fault on foot in 1895, predicting that the cycle would repeat. It has. Los Angeles weighs approximately four billion tons. It sits on the Pacific Plate. The plate is moving northwest at the speed of a human fingernail growing. The friction holding it in place has held for three hundred and forty-six years on the southern section. The plates do not consult retrofit inventories. They do not wait for emergency preparedness drills. They are governed by the conservation of momentum, the friction coefficient of granitic rock against itself, and the temperature of the lower crust. Every one of those parameters has been measured. None of them favors delay. 00:00 346 Years of Silence 00:29 The Fault Across California 02:05 Reading Earthquakes in the Ground 03:39 What This Video Will Reveal 04:09 Fort Tejon, 1857 08:10 Kerry Sieh and Pallett Creek 10:36 The 20-Foot Slip Deficit 11:45 The USGS ShakeOut Scenario 13:17 Gas, Fire, Water, and Roads 15:22 Beyond the Conservative Model 16:03 The San Gorgonio Pass Knot 18:29 Carrizo Plain and Plate Motion 20:18 Andrew Lawson and 1906 22:21 Why Northridge Was Not The Big One 24:31 A Fault Older Than California 27:18 The Missing Fourth Date PEER-REVIEWED SOURCES Sieh, K. (1978). Prehistoric large earthquakes produced by slip on the San Andreas fault at Pallett Creek, California. Journal of Geophysical Research, 83(B8), 3907–3939. doi:10.1029/JB083iB08p03907 Sieh, K., Stuiver, M., & Brillinger, D. (1989). A more precise chronology of earthquakes produced by the San Andreas fault in southern California. Journal of Geophysical Research, 94(B1), 603–623. doi:10.1029/JB094iB01p00603 Zielke, O., Arrowsmith, J. R., Grant Ludwig, L., & Akciz, S. O. (2010). Slip in the 1857 and earlier large earthquakes along the Carrizo Plain, San Andreas fault. Science, 327(5969), 1119–1122. doi:10.1126/science.1182781 Philibosian, B., Fumal, T., & Weldon, R. (2011). San Andreas fault earthquake chronology and Lake Cahuilla history at Coachella, California. Bulletin of the Seismological Society of America, 101(1), 13–38. doi:10.1785/0120100050 Jones, L. M., et al. (2008). The ShakeOut Scenario. U.S. Geological Survey Open-File Report 2008-1150. doi:10.3133/ofr20081150 Field, E. H., et al. (2014). Uniform California Earthquake Rupture Forecast, Version 3 (UCERF3). Bulletin of the Seismological Society of America, 104(3), 1122–1180. doi:10.1785/0120130164 Kanamori, H. (1977). The energy release in great earthquakes. Journal of Geophysical Research, 82(20), 2981–2987. doi:10.1029/JB082i020p02981 Hauksson, E., Jones, L. M., & Hutton, K. (1995). The 1994 Northridge earthquake sequence in California. Journal of Geophysical Research, 100(B7), 12335–12355. doi:10.1029/95JB00865 Lawson, A. C. (chair) (1908). The California Earthquake of April 18, 1906: Report of the State Earthquake Investigation Commission. Carnegie Institution of Washington, Publication 87.