Data will help make future structures even safer
ARCHIVE News Release# 2010-02
January 28, 2010
SACRAMENTO – To help gather vital data about earthquakes, the California Geological Survey (CGS) recently installed instruments on Pier T of Port of Long Beach. The monitors are not an early warning system; they help make future construction more quake-resilient and guide emergency response.
“The Navy transferred the pier to the Port of Long Beach, and we worked to install our instruments as the pier was revamped to support cranes that offload container ships,” said Dr. John Parrish, California’s State Geologist and head of CGS. “These accelerographs gather important information about how earthquake shaking impacts structures and transportation infrastructure. Ultimately these data will enhance our response to quakes and allow improved designs to reduce future damages.”
CGS’ Strong Motion Instrumentation Program (SMIP) placed 15 sensors on the deck and in the concrete pilings under the pier, and three in the area where goods offloaded from ships are temporarily stored.
“We’re very pleased that the Port of Long Beach allowed us to instrument this facility,” said Dr. Anthony Shakal, who heads the SMIP program. “We now have a good number of sensors at the state’s major ports – Los Angeles and Oakland in addition to Long Beach. This is important because port facilities around the world typically haven’t fared well in large earthquakes. You find some of the poorest soil conditions where the land meets the sea. There is major and critical infrastructure built atop mud and sand hundreds of feet thick.”
The Port of Long Beach is planning to build a new administration building in the next few years. SMIP will have a unique opportunity to install instruments under the building, inside and outside the piles that will be driven deep into the underlying materials to support the structure.
“We’ve never measured the ground movement under a building before,” Shakal said. “There are a lot of computer models for this, but there’s nothing to check them against. This will be an important step to getting information that will either verify the models or prompt the engineering community to re-think some things.”
Immediately after an earthquake, information gathered by the sensors is transmitted to central computers at headquarters in Sacramento for processing and the production of a digital “ShakeMap” of the intensity of shaking in the area. Among other things, the ShakeMap helps emergency responders determine where the highest levels of shaking have occurred and thus where critical infrastructure elements – such as transportation corridors and water lines – are most likely to be damaged. In the long term, however, SMIP’s data is even more valuable for its influence on building codes and practices.
“Over the years, these instruments have produced a great deal of information beneficial to the scientific and engineering communities,” Shakal said. “California’s seismic codes and construction practices are perhaps the most effective in the world in guiding structural design to minimize critical infrastructure damage in the event of a large earthquake.”
CGS, which celebrates its 150th anniversary this year, established SMIP in 1971 after the damaging San Fernando earthquake. SMIP has installed and maintains more than 5,000 recording instruments at more than 1,100 locations statewide, including the Vincent Thomas suspension bridge near the port, the Long Beach and Los Angeles City Halls, and interchanges on Interstate 5 and Interstate 10. The Applied Technology Council in 2006 honored SMIP as one of the top seismic programs of the 20th century.
The goal of SMIP and its partners in the California Integrated Seismic Network (CISN) – the California Institute of Technology, UC Berkeley, and the U.S. Geological Survey – is to have at least one instrument in every ZIP code in the state.
SMIP data is available online at conservation.ca.gov and strongmotioncenter.org.