Is your building safe after an earthquake? These cheap sensors could tell you
Source: Science Magazine
JANTETELCO, MEXICO—On 19 September 2017 at 1:14 p.m., the ground lurched under Mariano Matamoros Elementary School here. The earth had ruptured just 40 kilometers away, at the epicenter of a 7.1-magnitude earthquake that killed nearly 400 people across central Mexico. Adobe buildings, common in this small town, cracked and crumbled. At the school, a second-floor landing tilted precariously above a cracked concrete column. All the students and teachers evacuated safely, and the building was repaired, but for months, young students feared returning to second-floor classrooms, says Principal Casimiro Enríquez Vergara. "Any loud sound we hear now, we think it's an earthquake," he says.
Now, this school has become one of the first in Mexico to be equipped with a cheap sensor system that, in a future earthquake, will monitor shaking and automatically assess whether damage has occurred. The ideas behind the system, called Pulse and sold by the Mexico City–based company Grillo, are not new. Earthquake engineers have long put sensors in large, critical structures such as bridges and skyscrapers, so they can look for clues to hidden, deadly damage after a quake. The plummeting cost of sensors and the cloud computing needed to process all the data is allowing researchers in both the public and private sectors to deploy the sensors in many parts of the world. Scientists hope the systems can save lives and help prioritize repairs in the wake of deadly earthquakes.
"It's been a dream of the engineering community for a long time," says Thomas Heaton, a civil engineer and geophysicist at the California Institute of Technology (Caltech) in Pasadena. He compares the field, known as structural health monitoring, to "taking a building's blood pressure" and hopes for a day when all buildings in seismically risky regions are continuously monitored. Thanks to the newly affordable equipment, "it's really feasible" now, Heaton says.