Hurricane Irma is so strong it's registering on devices designed to detect earthquakes
As powerful Hurricane Irma roars across the Caribbean and approaches the U.S., it is showing on seismometers — equipment designed to measure earthquakes.
Seismometers have picked up "noise" from Irma on islands such as Guadeloupe, St. Martin, Barbuda and Puerto Rico, according to Stephen Hicks, a seismologist at the University of Southampton in the United Kingdom. Devices in the U.S. will start to pick up the readings as well as Irma gets closer to the mainland.
The noise is likely caused by high winds — which cause tiny motions in the ground — and also by trees swaying in the wind, which also transfers energy into the ground, Hicks said.
The seismometer in Guadeloupe is located close to the ocean, so waves crashing along the coastline reverberated around the island, also generating seismic energy, Hicks added.
It's actually not unusual for large storms to register on seismometers for hours to days as they pass over.
"We saw this for Hurricane Harvey on seismometers located close to Houston," he said. In the U.K., wintertime storms can sometimes make it hard for seismologists to see small earthquakes because the noise level generated by storms is so high.
The hurricane isn’t creating earthquakes, he said. "Earthquakes occur tens of (miles) deep inside Earth’s crust, a long way from the influence of weather events, and there is no evidence to suggest that hurricanes and storms directly cause earthquakes."
The readings aren't measured like earthquakes, either: There's no magnitude involved.
"Because the hurricane is not a single, sharp event like an earthquake we cannot determine an equivalent earthquake magnitude — the calculation would not make any sense," he said.
Unfortunately, as the hurricane gets closer to seismic stations, the instruments are going offline, probably due to power outages or damage to telecommunications systems.