Definition of an Earthquake Early Warning
Earthquake early warning consists of people being able to quickly detect that an earthquake is coming, a real-time assessment of the shaking hazard, and the general public being alerted before the shaking begins. The warning time can range from a few seconds. The amount of alert time is based on where people are located and the size of the earthquake.The farther a person is from the epicenter, the more warning time that they get. The bigger the earthquake is, the stronger it will shake at further distances. If people can be warned ahead of time, they will know how strong the shaking will be there where they are and how long they have before the shaking will begin (the warning time).
Who Will Benefit From The Early Warning System?
When an earthquake is coming, we could use some time to allow us to get a place where we will be safe from the upcoming storm, like under a table where we are safe from bookcases, ceiling lights, and fixtures. During the earthquake in Northridge in 1994, over fifty-percent of the injuries were caused by people being hurt by non-structural (falling) hazards. Even though it was not a very big earthquake, the cost of the injuries was approximately $2-3 billion. If people had been warned to take cover prior to the earthquake, these injuries would have been cut in half. Businesses, corporations, and agencies can not only protect their employees, they can also use automated control systems to cut down on personal injuries and damage to their property.
Corporations, institutions, and agencies can not only protect their staff members, they can also use automated control systems to further reduce how many people get hurt and how much of their property is damaged. They can do this by slowing trains down or stopping them, putting hazardous chemicals and machinery in an area by themselves, turning on the emergency generators, moving data to an off-site storage unit, etc. Physicians can lift the scalpel out of a patient before the storm hits so no one gets hurt by it. The metro/commuter rail system that is located in the San Francisco/Bay Area (BART) already uses alerts from ShakeAlert to slow their trains down when an earthquake is coming.
ShakeAlert is the name of the public earthquake warning system that is currently being used in California, Washington State, and Oregon. The Elarms algorithm was created the UC Berkeley Seismological Laboratory is one of the core ShakeAlert algorithms and is usually the source of the first alert message.
When an earthquake starts, non-damaging P-waves are detected by sensors throughout a region. Then data about the shaking is sent to a central processing center, where the site and location of the earthquake are determined. Then a forecast of the shaking intensity at locations is sent out seconds to minutes prior to the damaging S-waves arriving.
If more storm centers utilize ShakeAlert, then more people will have more warning before earthquake hits and then they can take cover in a safe place sooner. That will result in fewer people being hurt by the earthquake. ShakeAlert is a big help to those who are experiencing the stress and trauma of an earthquake and the more it continues to be used, the less stress and trauma will come about as a result of an earthquake.