Airborne infrasound can improve can improve tsunami warnings and other emergency responses.
Scientists from the US state of Alaska have found that sensors that detect changes in atmospheric pressure due to earthquakes can receive data on large earthquakes and explosions exceeding the maximum capabilities of many seismometers, reported the electronic edition “Euricalert”.
Sensors that detect inaudible infrasounds in the air can improve tsunami warnings and other emergency responses while reducing costs.
The study by experts from the Geophysical Institute at the University of Alaska in Fairbanks shows that these devices can determine the magnitude of earthquakes more accurately than some seismographs. The initial tsunami warning is based only on the estimated magnitude and location.
Infrasound sensors are commonly used for other purposes such as detecting mine explosions or nuclear detonations. They also detect landslides, erupting volcanoes or meteors entering the Earth’s atmosphere.
“What we’ve done is use infrasound for a purpose it’s not really intended for,” says Ken McPherson of the Alaska Geophysical Institute. “We found that it works well for providing complete data for strong earthquakes.”
These infrasound detectors are typically used for non-seismic purposes, including detecting explosions in the mining industry or nuclear detonations. They also record landslides, erupting volcanoes or meteorites entering the Earth’s atmosphere.
The sensors register changes in atmospheric pressure caused by infrasound waves, whose frequency is lower than that which humans can hear.
Infrasound sensors can record the full range of Earth’s surface motion during an earthquake by picking up changes in atmospheric pressure caused by shifting layers.
Seismographs detect the actual movement of the earth’s surface. The problem with them is that they have an upper limit, which means that data for some large earthquakes that exceed this limit may be missing. Seismographs can also fail to detect weaker tremors if their epicenter is too close to the instrument.
Seismologists can prevent these gaps, including by using strong motion sensors. They have no limitations when it comes to strong tremors, but are more expensive and less accurate in detecting data from weaker ones.
Infrasound sensors are cheaper and operate at the same speed as seismographs. This is especially important in the event of a tsunami. The US National Tsunami Warning Center has only four minutes to send out notifications the moment an earthquake strikes.
Photo by Ray Bilcliff: https://www.pexels.com/photo/giant-tsunami-wave-9156792/