29 de septiembre de 2014
Seismologist Says It’s Time to Talk About Earthquake Early Warning
Thursday’s 6.2 earthquake in Southcentral Alaska struck without warning. Because that’s what earthquakes do here in Alaska. But state seismologist Michael West says it’s time for Alaskans to discuss the possibility of an earthquake early warning system.
“You can think about it as throwing a rock in a pond and the waves ripple out at some speed, but it’s not instantaneous,” he says. “If you can detect those ripples before they get to you, like with sensors very close to the source, you can very easily have seconds, in some cases, maybe a minute or two of forewarning. “
The warning time would vary, depending on the location and type of earthquake. West says for a quake like the one Anchorage felt yesterday, the warning would likely only be a few seconds.
“If the 1964 earthquake, or something comparable were to occur going forward, an earthquake early warning could easily be able to provide tens of seconds before the strongest shaking.
So what can you do in tens of second? It’s probably not enough time to evacuate a building, but West says it could be enough for an automated shut down of a natural gas pipeline.
“Stoplights,” he says. “Turn all the stop lights red to bring all traffic to a halt, in advance.”
It could, he says, alert a surgeon just picking up a scalpel.
Japan’s early warning system stopped bullet trains and forced open elevator doors during the massive 2011 earthquake. Switzerland and Mexico also have warning systems. California is building one, but West says there’s nothing in development for Alaska. To get such a system, he says the state would need more seismic stations.
“The reason for that is very simple: The closer you have a sensor to the start of the earthquake, the epicenter, the more quickly you can detect it,” he says.
It would also require fast data communication lines and a way to deliver useful messages to residents without inducing panic. West says the cost would likely run to the tens of millions.
“Let me be honest. Some of this is expensive, and we need to decide whether or not that’s a priority for us or not. I think that’s a very logical, very reasonable discussion to have,” he said. “My concern is we’re not really talking about it very much.”
West was in Washington, DC this week to rally support for permanent seismic monitors in northern and western Alaska. They’re important for the Alaska Earthquake Center’s ongoing data collection, but West says they’d also be a good first step toward an early warning system.