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

Updated 44 mins ago - Politics & Policy

Coronavirus dashboard

Illustration: Annelise Capossela/Axios

  1. Politics: Trump says if Biden's elected, "he'll listen to the scientists"Trump calls Fauci a "disaster" on campaign call.
  2. Health: Coronavirus hospitalizations are on the rise — 8 states set single-day coronavirus case records last week.
  3. States: Wisconsin judge reimposes capacity limit on indoor venues.
  4. Media: Trump attacks CNN as "dumb b*stards" for continuing to cover pandemic.
  5. Business: Consumer confidence surveys show Americans are getting nervousHow China's economy bounced back from coronavirus.
  6. Sports: We've entered the era of limited fan attendance.
  7. Education: Why education technology can’t save remote learning.
2 hours ago - Health

Trump attacks CNN as "dumb b*stards" for continuing to cover pandemic

President Trump attacked CNN for continuing to cover the coronavirus pandemic, calling the network "dumb b*stards" at a campaign rally in Prescott, Arizona on Monday.

Why it matters: The president's attacks on the media and Anthony Fauci, the government's top infectious-disease expert, come as coronavirus cases and hospitalizations are again surging across the country, just two weeks out from Election Day.

3 hours ago - World

Deal to remove Sudan as terror sponsor paves way for Israel move

President Trump announced Monday that he will be removing Sudan from the State Department’s state sponsors of terrorism list after the Sudanese government agreed to pay $335 million in compensation for families of American victims of terrorism.

The big picture: Trump's announcement is part of a wider agreement that is expected to include moves from Sudan toward normalizing relations with Israel.