China News Service, August 26. According to the US "World Journal" report, recently, Kong Qingkai, a Chinese researcher at the Seismology Research Office of the University of California, Berkeley, said that he participated in the study of the earthquake early warning system "My Shake", which can be used on Android phones. The data from the acceleration sensor is used to calculate the seismic data to give early warning.

  Currently, this idea has been adopted by Google. The principle of the research is that the mobile phone automatically records the vibration, enters the data into the network and analyzes it instantly, and shares the earthquake scale, location and estimated vibration area with all people searching for earthquake keywords. Google's long-term goal is that even if a country does not have an earthquake warning network, it can use the mini seismograph of a mobile phone to warn.

  It is understood that Kong Qingkai has been involved in seismic research for 9 years, and his PhD supervisor in seismology is Richard Allen, a professor in the Department of Earth and Planetary Sciences at the University of California, Berkeley and director of the Seismology Laboratory. Allen led the research and development of the mobile phone application "My Shake", which was released in 2019 with the Governor's Emergency Services Office and other departments, making it the first state-level earthquake warning system in the United States. Through the earthquake early warning system operated by the geological survey, "My Shake" can provide warnings.

  The earthquake early warning system detects the first seismic wave (called P wave) of an earthquake to warn of it. The seismic wave travels faster than the more destructive S wave. The radio waves used for communication are much faster than seismic waves. The farther the receiver is from the epicenter, the greater the delay between P wave and S wave, and the longer the warning time of "My Shake".

  Kong Qingkai said that the "My Shake" early warning system is mainly composed of two parts. One is the enabled mobile phone app to provide early warning through the earthquake early warning system; the other is to use the mobile phone's own acceleration sensor to detect earthquakes and provide early warning. Google cooperation. As long as it is an Android smartphone, even if there is no App installed, it can detect earthquakes with the built-in acceleration sensor.

  Mobile phone acceleration sensors can sense acceleration in different directions, and then record, measure and even warn of earthquakes. The responsibility of the researcher is to use the existing hardware sensors of the mobile phone to develop algorithms and software to turn the use of hardware into an earthquake measuring device. Traditional seismic stations use large sensors to measure seismic waves, and mobile phones are equivalent to small sensors. The system algorithm is more intelligent, which can distinguish the difference between the mobile phone's artificial shaking and earthquake vibration, and send the data back to the data center to calculate the epicenter, magnitude and other data.

  Kong Qingkai said that the initial stage of the study faced doubts. Some people think that the large-scale sensors of traditional seismic stations are sensitive and expensive to build. California can measure earthquakes of magnitude 6-7 in Japan, while cell phone sensors only cost US$2. Can it really provide early warning?

  In this regard, after the earthquake, Kong Qingkai and his team used the collected data to conduct simulations and found that in the 2016 Borrego Springs earthquake in Southern California, the mobile phone warned for 6 seconds before the strong earthquake reached Palm Springs. In the 2018 Berkeley 4.4 earthquake, the warning time of mobile phones in the San Francisco Bay Area also varied from a few seconds.

  Kong Qingkai said that the current use of mobile phones to calculate and warn earthquakes is still in the research and development stage and has not been put into use in large quantities. In addition to Google, all mobile phone users who have installed the mobile program "My Shake" will also collect vibration data and upload them to Berkeley's laboratory for analysis. (Liu Xianjin)