Can the Seismic Alert System of Mexico serve as an earthquake early warning system model for the whole world?
The Friday before Easter, an earthquake originated off the west coast of Mexico, about 80 miles up the coast from Acapulco. Twenty miles of earth ripped apart and shifted along the Motagua and Chixoy-Polochic fault complex at 9:27 a.m. In less than 10 seconds, officials in seven Mexican cities were notified of the 7.2-magnitude event via the Seismic Alert System of Mexico (SASMEX), one of the world’s most effective earthquake early warning systems.
The earthquake fell in Holy Week in Mexico, which turned out to be a minor blessing. Schools were closed, and many city streets were less crowded than usual as people were away visiting family. The earthquake knocked over some fences and trees, broke some windows and plates, but there have been just three reported injuries, and no reported deaths.
Circumstance and luck figured into the relatively favorable outcome, but the nation’s earthquake early warning system may have helped, too, as citizens heard sirens and radio broadcasts, read text messages, or saw emergency television broadcasts warning them of the imminent danger. Some had more than a minute of notice, while those in the closest cities still had about 30 seconds to get somewhere safe.
Just one month earlier, researchers were testing SASMEX from the exact location where the earthquake occurred on Good Friday, making sure the system upgrades added in recent years were working properly. After the earthquake, officials reported that it performed perfectly.
Acapulco was the closest major city to the event, about 80 miles away. SASMEX detected the initial earthquake and judged its strength to be greater than magnitude 6.0, which meant notifications must be issued to the regions that would be affected, directly to state officials and also through emergency notification systems. In the end, the earthquake had been detected by 66 field stations. Notifications were simultaneously issued through siren, AM and FM radio, opt-in text message services, and television broadcast. This gave the people in Acapulco 25 seconds of advance notice, according to the Center of Instrumentation and Seismic Record. Chilpancingo got 35 seconds notice, Morelia got 58 seconds, and inhabitants of Mexico City got up to 74 seconds.
SASMEX began its life as a project in 1990, and has come a long way since then -- it wasn’t until recently that it began operating in such a sophisticated manner. A few years ago, Mexican officials realized that SASMEX wasn’t living up to its potential, and they asked a company called AtHoc to help. Technically, Mexico has been capable of this type of early warning and notification for many years, said Efraim Petel, AtHoc’s vice president of global public safety. The problem, he said, was that the various agencies and states had not organized around the technology and infrastructure they had.
The system’s sensors were picking up hundreds of earthquakes each year, Petel said, but that’s not of much use if there’s no way to instantly notify people of the impending danger. The damage wave of an earthquake, called an S-wave, travels extremely fast – at about 60 percent the speed of sound. Government can’t afford the extra time it takes after receiving an early warning notification to then issue that warning to the people – if there’s a big earthquake, a warning needs to go out to everyone immediately, and that’s what AtHoc has helped Mexico accomplish over the last few years.
This latest earthquake is a validation of the work AtHoc has been doing. “It was so successful that we got an email from the Japanese manager of their earthquake warning system, who felt this will [be] the model for the whole world," Petel said. "And it brings lots of hope for other locations."
One location hoping to institute a more sophisticated early warning system is the western United States. California has sensor stations in place for earthquake detection, but an early warning system like the ones in Mexico and Japan would cost California something like $83 million for five years of funding. This April, the California Institute of Technology and the United States Geological Survey announced the city Long Beach, Calif., will pilot the technology that could grow into a more sophisticated California Integrated Seismic Network (CISN) Earthquake Early Warning System (EEWS). But as USGS Research Geophysicist Elizabeth Cochran told Government Technology in October 2013, the legislation that supports the creation of this system means little without a reliable source of long-term funding.
In Mexico, Petel said, the hardest part of getting the system working was to get all the state agencies and officials to cooperate. One way they overcame that challenge, Petel said, was to complete work in stages. For example, they focused on one part of the system, like sirens, and made sure that worked well before moving on. And as they progressed, he said they saw greater commitment from various state agencies as they saw value in the project.
Mexico also has an advantage over the U.S. in that its federal government played a strong role in coordinating interstate efforts on this project, said Cris Paden, director of communications for AtHoc, adding that in the U.S., the federal government doesn’t have that level of involvement.
“Is it the National Geological Survey or not? And if it is, then the feds ought to be involved,” Paden said. “It’s a little bewildering that Mexico is ahead of the United States when it comes to warning and communicating about earthquakes.”
AtHoc helped Mexico make SASMEX smarter and more configurable. It can be adjusted to ignore earthquakes under a threshold. If an event is measured at less than magnitude 5.0, no one is notified. If an earthquake is detected between magnitude 5.0 and 6.0, only officials in the relevant states are notified, but the public is not notified directly. There is also a level of customization in the ability to notify only those regions that need to be notified based on their distance from the epicenter. Once alerts are issued, tens of thousands of receivers in participating cities receive the signal.
The system worked exactly as it was supposed to, and officials will continue to add features, said Juan Manuel Espinosa Aranda, director of Mexico's Center of Instrumentation and Seismic Record. They are now looking to upgrade the system so that information, such as the strength of the earthquake, can be sent to the receivers.
When it came to getting this technology working, Aranda said, the main problem was dealing with a new administration every six years, because all negotiations are reset when someone new takes office. Another problem, he said, is that major earthquakes don’t happen that often, so government places little attention on the challenges of building an early detection system until a big earthquake finally hits. That was certainly the case in Mexico, as its own system began development in 1990, following the 1985 8.1-magnitude Mexico City earthquake that is estimated to have killed as many as 40,000 people.
And to ensure that an earthquake early detection program doesn’t die, Aranda said, funding must be secured for a long period, such as 10 or 20 years.
While Mexico was lucky that no one was killed in the Good Friday earthquake, that earthquake had only about 10 percent the power of the 1985 event. Some scientists predict that the 20 miles of fault that shifted in this most recent earthquake was tiny compared to what could be coming to the region in coming years. Some predict that much larger events are overdue, including events that could start with 250 miles of fault line shifting.
In the western U.S., too, large earthquakes are expected; in the Pacific Northwest, scientists believe an earthquake larger than 9.0-magnitude could come at any time because the plates shifting off the coast have been locked for a long time. The last huge earthquake in the region was in 1700. The event was so powerful it created a tsunami in Japan.