The 2003 San Simeon earthquake struck at 11:15 PST (19:15

UTC Coordinated Universal Time (UTC) is the primary time standard globally used to regulate clocks and time. It establishes a reference for the current time, forming the basis for civil time and time zones. UTC facilitates international communica ...

) on December 22 on the

Central Coast of California The Central Coast is an area of California, roughly spanning the coastal region between Point Mugu and Monterey Bay. It lies northwest of Los Angeles and south of the San Francisco Bay Area, and includes the rugged, rural, and sparsely populat ...

, about northeast of

San Simeon San Simeon ( Spanish: ''San Simeón'', meaning "St. Simon") is an unincorporated community on the Pacific coast of San Luis Obispo County, California, United States. Its position along State Route 1 is about halfway between Los Angeles and San ...

. Probably centered in the Oceanic fault zone within the Santa Lucia Mountains, it was caused by

thrust fault A thrust fault is a break in the Earth's crust, across which older rocks are pushed above younger rocks. Thrust geometry and nomenclature Reverse faults A thrust fault is a type of reverse fault that has a dip of 45 degrees or less. I ...

ing and the rupture propagated southeast from the

hypocenter A hypocenter or hypocentre (), also called ground zero or surface zero, is the point on the Earth's surface directly below a nuclear explosion, meteor air burst, or other mid-air explosion. In seismology, the hypocenter of an earthquake is its ...

for 12 miles (19 km). The most violent ground movement was within 50 miles of the

epicenter The epicenter (), epicentre, or epicentrum in seismology is the point on the Earth's surface directly above a hypocenter or focus, the point where an earthquake or an underground explosion originates. Determination The primary purpose of a ...

, though the earthquake was felt as far away as Los Angeles. With a moment magnitude of 6.6, it was the most destructive earthquake to hit the United States since the Northridge quake of 1994.

Damage

The area around the epicenter being sparsely populated, the most severe damage was in Paso Robles, 24 miles (39 km) east-southeast. Two women were killed when the Acorn Building, an unreinforced masonry structure built in 1892, collapsed. Other unreinforced masonry buildings, some more than a century old, were extensively damaged. No structure that had even partial

retrofitting Retrofitting is the addition of new technology or features to older systems. Retrofits can happen for a number of reasons, for example with big capital expenditures like naval vessels, military equipment or manufacturing plants, businesses or go ...

collapsed. Two sulfur

hot spring A hot spring, hydrothermal spring, or geothermal spring is a Spring (hydrology), spring produced by the emergence of Geothermal activity, geothermally heated groundwater onto the surface of the Earth. The groundwater is heated either by shallow ...

s in Paso Robles erupted after the earthquake. One was underneath the parking lot of the recently opened city hall/library building. There was formerly a bath house at the location, and the spring was capped after it closed down. Hot water and

sediment Sediment is a solid material that is transported to a new location where it is deposited. It occurs naturally and, through the processes of weathering and erosion, is broken down and subsequently sediment transport, transported by the action of ...

were released at a rate of about 1,300 gallons per minute (4,900 liters per minute), forming a large

sinkhole A sinkhole is a depression or hole in the ground caused by some form of collapse of the surface layer. The term is sometimes used to refer to doline, enclosed depressions that are also known as shakeholes, and to openings where surface water ...

and endangering the building. Emergency efforts saved the building. However, it took until 2010 to fully repair the damage and fill in the hole. This was mainly caused by the requirement for a full Environmental Impact Study, and the inability to do any work on the project, other than the initial emergency work. Another hot spring flowed out of the embankment at the Paso Robles Street exit on

U.S. Route 101 U.S. Route 101, or U.S. Highway 101 (US 101), is a major north–south highway that traverses the states of California, Oregon, and Washington on the West Coast of the United States. It is part of the United States Numbered Highway Syst ...

. There was a wrongful death lawsuit filed by the relatives of the 2 women killed in the earthquake against Mary Mastagni, and several trusts which owned the Acorn Building. The jury found Mastagni negligent in the care and maintenance of the Acorn Building, due to not retrofitting the building, in violation of city ordinances. The jury awarded nearly $2 million to the plaintiffs. Outside of Paso Robles the damage was less severe, with unreinforced masonry buildings taking minor to moderate damage. Buildings even 40 miles from the epicenter in

San Luis Obispo ; ; ; Chumashan languages, Chumash: ''tiłhini'') is a city and county seat of San Luis Obispo County, California, United States. Located on the Central Coast (California), Central Coast of California, San Luis Obispo is roughly halfway betwee ...

suffered minor damage such as ceiling tiles falling.

Brick A brick is a type of construction material used to build walls, pavements and other elements in masonry construction. Properly, the term ''brick'' denotes a unit primarily composed of clay. But is now also used informally to denote building un ...

veneers were also disproportionately affected. In addition,

water tank A water tank is a container for Water storage, storing water, for many applications, drinking water, irrigation, fire suppression, farming, both for plants and livestock, chemical manufacturing, food preparation as well as many other uses. Water ...

s in Paso Robles, Templeton and Los Osos were damaged. Residential buildings, predominantly one- to two-story wood-frame structures, weathered the quake with little or no damage. The building that housed Atascadero's City Hall was damaged and vacated shortly after the quake. After extensive repairs, it reopened in August 2013. Some wineries, especially those near the epicenter along State Route 46, reported damage such as barrels toppling and bursting. The Mission San Miguel Arcángel had $15 million worth of damage. The earthquake also caused extensive damage to George H. Flamson Middle School. The main building was damaged and had to be demolished in 2004. A new building reflecting the original 1924 building was opened for use in August 2010. In Templeton, Bethel Lutheran Church (ELCA), sustained major damage to its 110+ year old building and the apse had to be rebuilt.

Aftermath

Following the event, California enacted A.B. 2533, amending the California Business and Professions Code § 8875.8, requiring that certain unreinforced masonry buildings that have not been seismically retrofitted have posted notice of the potential earthquake hazard. The law was called ''Jenna's Bill'', after Jennifer Myrick, who died in the quake.

Faulting

The area where the quake struck displays a complex faulting geometry, between the active Oceanic Fault and the older Nacimiento Fault, along with possible interaction from the Hosgri and San Simeon segments of the mainly offshore San Gregorio-San Simeon-Hosgri fault zone.

Notes

Sources
2003 San Simeon Earthquake: Preliminary Earthquake Analysis
– California Integrated Seismic Network
Preliminary Observations on the December 22, 2003, San Simeon Earthquake
– Earthquake Engineering Research Institute
M6.6 – Central California
–

United States Geological Survey The United States Geological Survey (USGS), founded as the Geological Survey, is an agency of the U.S. Department of the Interior whose work spans the disciplines of biology, geography, geology, and hydrology. The agency was founded on Mar ...

External links

San Simeon, California
– Earthquake Engineering Research Institute * {{DEFAULTSORT:San Simeon Earthquake, 2003

2003 2003 was designated by the United Nations as the International Year of Fresh water, Freshwater. In 2003, a Multi-National Force – Iraq, United States-led coalition 2003 invasion of Iraq, invaded Iraq, starting the Iraq War. Demographic ...

2003 earthquakes History of San Luis Obispo County, California 2003 in California 2003 natural disasters in the United States Paso Robles, California Buried rupture earthquakes December 2003 in the United States

Damage

Aftermath

Faulting

See also

Notes

External links