Earthquake early warning system is nowadays the fastest way to detect earthquakes as well as evaluate the shaking hazard in real-time and inform people before shaking. The time to warn, however, depends on your place and how large the earthquake is, from a few seconds to a few minutes. Although different companies are already working on to provide more warning time to people, the greater the earthquake means, the more distance it shakes. An earthquake early warning should inform you how much shaking will be in your area and how long the shake will take (the time to warn).
Why Do We Need It?
An early warning system for an earthquake can warn people a few seconds to ten seconds before an earthquake happens. Information can be used in an earthquake to minimize harm, expenses and other losses. In Mexico, Taiwan, Japan, and many other countries, early warning systems are currently operating - but it's yet to be operated in the United States. Not really like SMS Broadcaster Machine, but with many similarities, ShakeAlert (a prototype early warning system) is now operated by the California Integrated Seismic Network in the California United States.
How Long Have Japan and Mexico Had These Systems?
Mexico was the first and foremost city that launched a public warning system back in 1991. Hence, it’s been around for more than two decades. Mexico City gets a warning worth more than 60 seconds - thanks to their source of the earthquake, which is about 186 miles from the city. Back in March, a magnitude of 7.4 was observed in Mexico City, causing a significant number of shocks, and the system issued warnings and people evacuated their houses.
The system of early warning in Japan is by far the most advanced. The gigantic experiment in 2011 was an earthquake with a magnitude 9. And effectively they gave an indication of an earthquake to the biggest neighboring town, Sendai. They had a warning of around 15 seconds.
How Does It Work?
Early warning earthquakes aim to rapidly detect earthquake initiation, to estimate the expected levels of earthquakes and warn before important earthquakes begin. This may be done by detecting the first power to radiate the P-wave energy from an earthquake, which is seldom harmful. This system then estimates the location and magnitude of the earthquake using the P-wave information. It uses this to evaluate the expected earthquakes in the region. The method can warn before the S-wave, which causes strong shaking, usually causing most damages.
According to the reports from CISN, depending on the distance of the epicenter of the earthquake, the warning time varies from 0 seconds to many seconds. It's enough for trains and airplanes to slow and stop, for cars to prevent entering tunnels and bridges, for dangerous machinery or chemicals to move away and be covered by desks, or for industrial systems to be shut down and isolated automatically. Such activities can decrease harm and loss of life during an earthquake.
How Can You Get Alerts Early?
The public dissemination of early warning alerts of earthquakes is not part of the current project - however, many countries are using bulk SMS blast to let as many people know as they can. That was mainly due to two reasons. The primary is that there are several areas where there aren't enough seismic stations for an early warning to recognize and characterize a new earthquake so fast. The second reason is that people, companies, and institutions should know first what they will do when the information is received to make early warnings useful.