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The Poás volcano as it erupts, taken by drone. Photo: Maarten J de Moor / OVISCORI

NEW ORLEANS — The Poás volcano in Costa Rica erupted suddenly and violently in late April, hurling chunks of rock into the air, destroying a nearby observation platform and wrecking a single piece of monitoring equipment: a sensor recording gas concentrations in the bottom of the crater. Since it’s not a good idea to walk into the heart of an erupting volcano, Maarten J de Moor, a volcanologist at OVISCORI in Costa Rica, sent in a drone.

Why it matters: de Moor’s drone (and his destroyed sensor) recorded changes in gas concentrations before the eruption, which he presented at the fall meeting of the American Geophysical Union. Such changes can signal if, and when, a volcano might erupt, and may even indicate how large the eruption will be. “If we can measure the gas compositions during eruptions, we can learn about those eruption processes,” says de Moor.

There are several different ways to monitor a volcano, including:

The old-fashioned way, where you dress head-to-toe in protective gear and gather fumes from a vent with a test-tube.

  • Pros: More tests can be run in the lab than can be run by an instrument.
  • Cons: It’s slow and can take months to do. And, although you can learn a lot about the volcano, real-time data is necessary to learn more about eruptions.

With a permanent sensor, like the MultiGAS sensor de Moor used.

  • Pros: Real-time monitoring of the volcano, from the volcanic crater itself.
  • Cons: These sensors can only measure the fluctuations of a few gases — so they're good for monitoring, but more detailed lab assessments are still necessary.

With a sensor (in de Moor's case, a miniature MultiGAS) attached to a drone.

  • Pros: You can fly into an active volcano after the eruption begins and get a birds-eye view with a camera.
  • Cons: Drones can only fly for so long on one battery charge, so monitoring isn't constant. Also, volcanos aren't very hospitable environments. de Moor estmates he can get about 20 flights out of a drone before it's destroyed — he lost one studying a different volcano already.

Yes, but gas sensors aren’t the only thing you can attach to a drone, and inactive volcanoes are also worth monitoring. That's why Einat Lev trekked for days to a remote Chilean volcano (accompanied by an entourage of horses and grad students), hauling batteries, an electric generator and a drone.

What she did: Lev, a volcanologist at Columbia University, uses the unmanned vehicles to scan the topography of cooled lava flows. Although you can get some idea of lava flow structure by looking at satellite images, the level of detail provided by drone can't be matched. By measuring the rocky dips and ridges, she can infer how fast the lava was moving, how hot it was, how liquid or solid it was. Lev also presented her findings at the meeting.

Why she did it: If we learn how a volcano erupted in the past, we might better understand how the same — or a different — volcano might erupt under similar circumstances.

A bonus: Drones might seem expensive, but it costs way more to do this sort of research from a helicopter.

Go deeper

4 hours ago - Technology

Facebook changes corporate name to Meta

Screen shot of CEO Mark Zuckerberg at the company's "Connect" virtual event

CEO Mark Zuckerberg on Thursday said the social media giant is renaming its company Meta.

Why it matters: The effort is meant to shift its image from a social media platform to a “metaverse” company that focuses on building virtual work and social communities.

Dan Primack, author of Pro Rata
4 hours ago - Economy & Business

Filings show Sweetgreen isn't profitable, despite claims

Illustration: Sarah Grillo/Axios

Restaurant chain Sweetgreen on Monday filed to go public, and revealed that it lost money in each year since 2014.

Why it matters: The company lied when it repeatedly told reporters it was profitable.

U.S. border cities again see low violent crime rates

Expand chart
Data: FBI, Kansas Bureau of Investigation, U.S. Census Bureau; Chart: Jared Whalen/Axios

Reported violent crime in the United States rose in 2020 for the first time in four years, but violent crime rates in 11 of the largest communities along the U.S.-Mexico border stayed below the national average, an Axios analysis found. 

Why it matters: Year after year, data showing low violent crime rates in majority-Mexican American and Mexican immigrant border communities dispels myths of the U.S.-Mexico border as a region filled with crime and chaos.