Earthquakes are one of the main natural hazards around the globe, while also being a major hazard for Israel. In 1927 a devastating earthquake inflicted huge damage in Jerusalem and Jericho, and an earlier earthquake in 1837 hit Zefat and Tiberias killing over 5000 people. Our researchers have also found evidence in geological and archaeological data of even stronger earthquakes in the past. If they occurred in the past, it is just a matter of time before they return. Our department has one of the main earthquake research groups in Israel. One of the important projects of this group is developing an early warning system for Israel. This involves detecting the initial seismic waves (p-waves) that do not produce much damage but arrive before the damaging surface waves (s-waves). Although the time between the arrival of these two wave types may only be seconds, it allows warnings to be made before the damaging shaking waves arrive that may cut of power, and damage infrastructures. For example, stopping sensitive operations, opening elevator doors at the next floor, stopping trains, and placing sensitive equipment in safe mode.
Understanding the history of earthquakes, the physics of rocks, the acoustic signatures produced by earthquakes, and the possible precursors to earthquakes will allow us to better prepare and warn the authorities and the public of earthquakes in the future.
In addition to studying the acoustic waves from earthquakes, researchers in our department also use man-made acoustic sources to probe the ground under our feet, whether to detect minerals, oil, gas or other underground cavities, such as sinkholes.