Efforts to set up a nationwide early-warning system for earthquakes recently took a giant step forward, as the government began preparing an international tender for construction of such a system.
The system will be based in part of the experience of California, where an experimental early-warning system was used in the big earthquake that hit a few days ago. It gave residents of big cities a 10-to-30-second warning.
The system will be run by the Geological Survey of Israel, which is under the auspices of the Energy and Water Resources Ministry. It is based on the recommendations of Israeli and international experts who convened at GSI two years. Among these experts was Prof. Richard Allen, one of the developers of the system used in California.
“Systems like this are operating in several countries, including Japan,” said Dr. Yariv Hamiel, head of GSI’s geological risks department. “But the geological and tectonic conditions there are different, so we decided to use the know-how that exists in California.”
The Israeli plan calls for building 120 to 150 stations with seismic sensors along the country’s main faults – the Dead Sea and the Carmel. The stations will be located either in existing municipal shelters or in special shelters built a few meters underground, to create an environment free of background noise.
The stations will transmit data about a quake to a computing center within seconds. The idea is for the sensors to detect the quake’s first seismic wave, which isn’t the one that causes the damage. This initial wave generally moves at a speed of five kilometers per second.
The computing center will focus initially on pinpointing the location of small and medium-sized quakes. The data it will thereby accumulate will enable it in the future to identify the location, depth and force of destructive quakes (those measuring 6 or more on the Richter scale) as soon as four different stations have reported in.
“The information will be given to the Home Front Command, and under the cabinet’s decision, all schools will be warned in the first stage,” Hamiel said. “At a later stage, nationwide warnings will be given,” similar to the sirens used today to warn of incoming rockets.
GSI researchers said it probably won’t be possible to warn people within about 25 kilometers of a quake’s epicenter. Jerusalem residents would get only a few seconds’ warning for quakes with an epicenter in the northern Dead Sea, but more than 20 seconds for a quake near Lake Kinneret and 10 seconds for one in Haifa. Tel Aviv residents would get a 20-to-30-second warning for a quake in the northern Dead Sea.
Aside from enabling people to seek shelter, these warnings would enable infrastructure systems and industrial plants to shut down or take other safety measures to avert disasters.
While the international tender for building the system is being prepared, GSI has begun selecting the locations for the warning stations, Hamiel said. It is also making the necessary preparations to obtain building permits.
In addition to the nationwide system, the Education Ministry has already installed localized warning systems that are supposed to detect minor quakes in 350 schools. By the end of next year, similar systems are slated to be installed in the remaining 1,600 schools built before 1980, which is when regulations requiring schools to be built to withstand earthquakes took effect. All new schools will also be built with such a system. However, there is still no evidence as to how reliable and effective these localized systems are.
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