Does climate change trigger earthquakes?

Maybe. Maybe not.

The question of whether climate change is contributing to the frequency of strong earthquakes remains unanswered, as do most questions confronting science, although we finally know the Earth isn’t flat and the sun doesn’t orbit around the Earth.

Hundreds of lives were lost last week in central Italy due to a major earthquake and subsequent aftershocks. On the same day quakes of similar magnitudes rocked Myanmar and offshore Japan. In Myanmar, there was significant structural damage, but no loss of life. In Japan, there was huge anxiety about a tsunami — a potentially devastating wall of water and a phenomenon not unfamiliar to the Japanese. The tsunami turned out to be an event that, thankfully, never transpired.

Three major seismic events on the same day. Hundreds dead. Hundreds more hospitalized. Billions in property damage. Three in the same day. Coincidence? Maybe. Maybe not.

On the maybe side, there’s a group of eminent geologists and geophysicists, including University College London’s Bill McGuire, professor emeritus of geophysical and climate hazards, that predicts climate change will trigger a series of life-threatening “extreme geological events,” including earthquakes, volcanic eruptions and tsunamis. “Climate change may play a critical role in triggering certain faults in certain places where they could kill a hell of a lot of people,” says Professor McGuire. He and some of his colleagues suspect the process may already be under way.

On the maybe not side, there’s at least one review of McGuire’s 2015 book on the topic (“Awakening the Giant”) that dismisses most theories linking climate change and earthquakes as “bunk.” And let us not forget the deniers, who put climate change and global warming in the same they-don’t-exist category as The Tooth Fairy and Santa Claus, ever vigilant in their efforts to not to be confused by the facts. For that crowd, “denial” is a river in Egypt and climate change is turning up the air conditioning or tossing another log on the fire.

In recorded geologic history, Maine has been more than less immune to earthquake death and destruction. You would have to set your watch back to March 21, 1904, when an earthquake with an estimated magnitude of 5.9 — lower than the recent 6.2 magnitude in Italy — rattled most of coastal Maine, including Portland, and also much of New England. The quake caused plenty of damage, especially to brick homes and businesses, but there were no injuries or deaths. Nonetheless, according to a headline in The Ellsworth American, local residents were “scared blue.” Whatever that means.

During 2006 and 2007, Bar Harbor and Acadia experienced several earthquakes, most centered just off the eastern shore of MDI. Before that time there had been just one report of an earthquake being felt on MDI — in 1995. Now referred to by geologists as “The Bar Harbor Series,” those earthquakes included more than 20 “trembles” under 2.5 on the Richter scale and two more at 3.0, one registering 4.2. Anything under 2.0 is considered to be a microquake, which is geologist parlance translates to “no big deal.”

There was cluster of microquakes in Maine earlier this year. In early February, there was a 3.3 magnitude quake with an epicenter in Passamaquoddy Bay six miles north of the Washington County community of Eastport. Five days later, a swarm of microquakes — as many as 21, but few strong enough to be felt — was detected, originating five miles east of Vanceboro in Washington County, one at magnitude 2.9, most at 2.0 or below. Since then, there’s been no seismic activity in or near Maine, according to Henry Berry, a bedrock geologist who monitors such things for the Maine Geological Survey.

“There’s a 98 percent probability that Maine won’t have a significant earthquake in the 6.0 to 7.0 magnitude range,” Berry said. “But that’s not zero. I think termites or snow will take my house down before an earthquake.”

Tom Walsh

Walsh, a Gouldsboro resident, is an award-winning medical and science writer.

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