One comment heard over and over in the analysis following the devastating 7.8 earthquake in Nepal is a variation on “they knew a big one was coming, they just didn’t know when.” The same is said here in California: depending on the expert asked and the current data, we’re expecting the big one, too. We just need to be prepared and build seismically-safe buildings.
In countries like Nepal, though, where most buildings are not built to withstand even earthquakes much weaker than the one that struck the country on Saturday, earthquakes can be much more devastating. One way to prevent the loss of lives is to get out of these seismically unfit buildings as fast as possible. Early warning systems don’t predict quakes but are able to warn when one is on the way. Hopefully, they are fast enough to provide that warning before the stronger shakes arrive.
According to a report I heard this morning on NPR (to which I will link as soon as the story is posted) there are two different mobile apps trying to implement such warning systems.
The first is MyShake. This app, developed by UC Berkeley’s Seismology Laboratory, uses crowdsourcing to try and detect a quake. How? By using accelerometers to detect a specific type of motion and sending that information to a server. “All we need is a telephone at the epicenter of the quake which detects it and sends the information (saying), ‘I felt a jolt, I am in this place” said Richard Allen, director of Berkeley’s lab. The current drawback of the MyShake system is that the servers cannot currently predict a quake weaker than 5.0. Says Allen: “while they have successfully programmed the phones to predictably measure earthquakes exceeding 5.0 magnitude, they have yet to fine tune “the backend”—that is, the server that can collect all the real-data, access whether a quake is actually taking place, calculate its magnitude, and then send a timely warning to all registered parties.” Another challenge for MyShake’s developers is that the system is difficult to test as it needs geographically widespread shaking data.
In California the early warning system currently being tested is not based on crowdsourced data. The Shake Alert app, developed by the United States Geological Survey and several university labs, including Berkeley’s, relies on a network of in-ground sensors that relay information to a server, which then sends out warnings via an app based on the user’s location. In the 6.0 Napa quake of August 2014, test users in Berkeley received alerts 5 seconds before the shakes arrived. Disappointingly, though,the app itself is still in beta mode.
Going back to Nepal, while a system like Shake Alert could be more reliable, the expense of placing the sensors, which themselves don’t come cheap, in Nepal’s challenging terrain will probably make this too costly a system, one Nepal couldn’t afford. On the other hand, with accelerometers and GPS sensors in so many smartphones and with smartphones being widely adopted in many developing countries, the MyShake app could be a good solution. According to the World Bank, mobile cellular subscriptions (per 100 people) for Nepal, as of 2013, were 77. For Haiti, another country hard hit by earthquakes, that number is 69. Even though MyShake can currently detect only quakes only above 5.0, just detecting those is a big benefit and any early warning system is better than none. Yet I say “could” because MyShake’s effect would depend on its trustworthiness. While an early warning system of even a few seconds can save a significant number of lives by warning people to run outside before the shakes arrive, if it generates too many false alarms then users will ignore it.
Yet, even with all the drawbacks, it’s encouraging to see products like the MyShack app. By realizing that many users already own smartphones, and using those smartphones to both detect quakes and warn residents might be the only early warning system developing countries will ever be able to use.
Update: the World Bank data refers to phones “able to connect to the PSTN network” with a voice connection. The number doesn’t imply a data connection. That said, I think it still makes a lot of sense to develop such apps. Even if smartphone adoption is not quite as widespread today, it will be tomorrow.