Is Volcanic Activity on the Rise? High-Profile Eruptions Don't Signal Increase in Volcanism

Nowadays, it's easy to feel like volcanoes are suddenly erupting on every corner of the planet. Hawaii's Kilauea has been putting hundreds of area houses at risk of encroaching lava for more than a month now. On June 3, Guatemala's Fuego volcano produced a burst of ash and rock in an eruption that has killed more than 100 people—and then neighboring Mt. Pacaya added another event to the mix.

But are volcanoes actually more active than usual, or are we just hearing more about their activity than usual? It turns out to be the latter, according to Ed Venzke, who manages the database of Smithsonian Institution's Global Volcanism Program.

The concern is understandable, he said. "If it's not part of people's daily lives and suddenly it's in the news, people sort of freak out a bit," Venzke told Newsweek.

But he indicated there's no need to worry. At any given time, there are almost always at least 20 eruptions unfolding, and so far this year 49 volcanoes have erupted at some point. Venzke said that puts us on track for a pretty standard annual tally compared to recent years.

Annual totals since 2000 have varied from 63 to 80 eruptions, which means that 49 by mid-June may feel higher than average. But that overlooks a major factor in these statistics, which is the duration of each individual eruption. In this case, an eruption is considered to be ongoing until a volcano has been quiet for three months, this year's tally was already at 37 on January 1.

Read more: What Are Lahars? Guatemala's Mt Fuego May Cause Volcanic Mudflows With Deadly Speeds

Those longstanding eruptions include both Kilauea, an eruption scientists define as beginning in 1983, and Fuego since 2002. (If that seems like a long time, a volcano in Vanuatu has been active since 1774.) Accounting for those continuing events, only 13 eruptions have actually begun this year so far. "It might even be on the lower end of the years," Venzke predicted of this year's annual total.

However, yearly totals are only insightful over a relatively short period of time. The more old data you add in, the more it looks like volcanic activity has spiked—but that's just an artifact of the data itself, not of volcanic activity. It reflects people and technology spreading out, increasing the proportion of eruptions that are actually reported, either from the ground or with satellite and other remote data. That means scientists know about more eruptions that are small or take place in isolated corners of the planet.

"We don't see any increase in eruptions, we see an increase in reported eruptions," Venzke said. "It's not a real increase, it's just an increase in our knowledge of what's going on."

Kilauea's continuing eruption as seen on June 5. Although the eruption is dangerous and has therefore been highly publicized, it doesn't mark an increase in volcanic activity worldwide. Terray Sylvester/Reuters

In order to avoid getting thrown off by seeing more eruptions overall, scientists looking to compare eruptions deeper into history focus just on larger eruptions. These eruptions have a much higher likelihood of making it into the documentary and geologic records scientists can reference.

Here, too, there's nothing extraordinary happening right now. "The number of large eruptions has been really, really stable," Venzke said. In fact, none of the eruptions this year have met scientists' qualifications for the two most serious categories of an eruption. Since 2000, there have been only two eruptions in these categories all told. "If anything, we're on the low end for large eruptions right now," Venzke said.

However, that doesn't mean we're "due" for another such eruption; it's all a matter of statistics.

Earth isn't betraying us in a sudden increase in volcanic activity, then. Of course, that doesn't mean the current volcanic activity isn't scary, or that it's not life-threatening for those living near these sites. But getting a better understanding on the planet's volcanic history is the only way we'll know for sure just what risks people living near volcanoes face, Venzke said.

"You have to know the history of a place to plan and take precautions for the future," he added.