This is part of our Road Trip 2018 summer series "Taking It to Extremes," which looks at what happens when people mix everyday tech with insane situations.

More than half a billion people on Earth live in the shadow of an active volcano. Growing up, I was one of them.

I spent my childhood in Tacoma, Washington, observing the gorgeous ticking time bomb that is Mount Rainier. From this vantage point 40 miles away, the mountain is pale blue and white, etched with the dark shadows of glaciers. Its silhouette sits in the foreground during sunrises throughout the year. In the summertime, the full moon rises right behind it.

Though Mount Rainier hasn't shown any hint of activity for a century, and its last major eruption was about 1,000 years ago, scientists believe the magma beneath the mountain could rise again.

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"At the most basic level, volcanoes are the inside of the Earth trying to get to the outside of the Earth," says Dave Pieri, a volcanologist at NASA's Jet Propulsion Laboratory.

Volcanoes gave us jarring reminders this year of their power to kill and to damage communities. In May, Kilauea on Hawaii's Big Island oozed lava and created volcanic smog in a slow, property-destroying crawl. The next month, Guatemala's Volcan de Fuego (Spanish for "fire volcano") exploded, burying villages with a fast-moving avalanche of ash, lava, rocks and mud. Official reports say 169 people died and 256 are still missing.

Fuego, Mount Rainier and Mount St. Helens are stratovolcanoes, which emit miles-high clouds of white-hot debris and pour out high-speed flows of ash and lava. In contrast, Kilauea is a shield volcano, which typically produces slow-moving lava. When Mount St. Helens erupted in 1980, it shot a column of volcanic debris and ash more than 15 miles into the air, killing 57 people, primarily from asphyxiation.

With more than 3 million people living near Mount Rainier and 2 million annual visitors to Mount Rainier National Park, the volcano's potential to kill with sudden ferocity is a major concern. But there's some good news: The instruments scientists use to spot signs presaging an eruption are constantly improving.

New digital tools let them quickly collect data on the small earthquakes that hint at a volcanic event. With lidar, which uses pulsed light to measure distances, volcanologists can create precise, 3D maps that look past trees and other plant life to reveal a volcano's true topography. And advances in portable mass spectrometers are letting scientists "see" what's happening inside a volcano and, you know, warn people before it blows.

Going digital

Lava, rocks and hot ash aren't the only things Mount Rainier could throw at us. The nearly 80,000 people living in Mount Rainier's river valleys, as well as the entire industrial Port of Tacoma, are in the path of one of the most dangerous by-products the mountain is capable of producing: the lahar.

A lahar is a fast-moving death sludge. It's what happens when hot rock debris instantly melts a glacier. The lava and debris, which can reach 1,400 degrees Fahrenheit, mix with the melted glacial water, and the resulting lahar pours down the mountainside, sweeping away everything and everyone in its path.

Lahars can have the consistency of wet cement and move at 50 miles per hour. When they finally come to rest dozens of miles from where they started, they might still be as hot as a roasted chicken just out of the oven (that's about 160 degrees Fahrenheit). When lahars come, you need to get to high ground -- fast.

"They can be hot, they can be fast, and they're thick and goopy and wreak havoc on structures," Paul Bodin, interim director of the Pacific Northwest Seismic Network, tells me as we hike a ridgeline facing Mount Rainier.

As I trudge up the hillside, I realize I'd be in trouble right now if I had to outrun a lahar.

Laura Hautala/CNET

Bodin and software programmer Jon Connolly, who both work at the University of Washington, are leading me up and down mountain trails strewn with slippery shale stones in some places and edged with patches of tiny purple wildflowers in others. We're headed to the seismology station at Mount Fremont Peak on the northern side of Mount Rainier National Park. After nearly 3 miles, we head down a steep meadow that might've given Heidi, the Swiss Alps orphan of children's literature, some serious vertigo.

We're here to scope out the isolated spot for a huge tech upgrade.

Once we arrive at the station, I see a very tall pole held up by guy wires, with an antenna and a solar panel at the top. Down the hill, a seismometer the size of a large soup can lies buried in the ground. Seismometers like this one emit electrical currents that change according to how hard they shake, producing data that scientists use to gauge a quake's magnitude.

"Volcanoes are the inside of the Earth trying to get to the outside of the Earth." Dave Pieri, volcanologist, NASA's Jet Propulsion Laboratory

The information is beamed out about 55 miles via FM radio before the data gets digitized. The problem, Bodin tells me, is that traveling that distance allows lots of noise to distort the data before it gets turned into ones and zeroes. The result is similar to taking an ultrahigh-resolution photograph of a faded Polaroid snapshot.

The seismology team expects a new array of technology will be installed this month: Computerized data loggers, about the size of extra-thick external hard drives, will digitize the data much earlier in the process to keep it as noise-free as possible. A new seismometer can provide richer data by measuring motion that's up and down, side to side and back and forth. That's good, Bodin tells me, because that's how the ground tends to move during an earthquake or an eruption.

Even better, the new seismometer can measure a much wider range of movement, from the small seismic wiggles that indicate shifting magma deep below the surface, to the larger shakes of earthquakes.

The higher-fidelity data will be a great boost to seismologists trying to predict eruptions, and the richer data set will help scientists distinguish when glaciers shift or ice falls.

Eruptions through the ages

Humans have always lived with the threat that the Earth will suddenly lose its mind and kill everyone near a geothermal vent.

A Neolithic mural painted around 6600 B.C. in central Turkey shows what appears to be the double-peaked Hasan Dağı volcano erupting next to a nearby village. To verify whether those twin peaks were, in fact, the now-dormant volcano, scientists at UCLA used zircon geochronology to date volcanic rock samples taken from the volcano, then compared the dates of those samples to the mural's archeological date.

"The overlapping time frames indicate humans in the region may have witnessed this eruption," Science News reported in January 2014.

Slightly more recently, between the 15th and 16th centuries B.C., the volcano on Thera (now Santorini, Greece), erupted in what geologists believe was the single most explosive event ever witnessed. Geologists believe the eruption measured 7 on the Volcanic Explosivity Index. The scale goes from 0 to 8, and each VEI is 10 times stronger than the preceding number. Many speculate that the Thera eruption, estimated to be the equivalent of 40 atomic bombs, was the inspiration for Plato's lost city of Atlantis.

Enlarge Image Laura Hautala/CNET

There are no eyewitness accounts of the blow that shook the ancient Minoan civilization, but there are plenty of details about the one on Krakatoa, Indonesia (VEI 6), in 1883. The devastating event was so loud it was heard 3,000 miles away. It spread volcanic ash across Asia, produced a 100-foot-tall tsunami, killed at least 36,000 people in hours, lowered global temperatures for the next five years and produced spectacular sunsets across the globe until 1886.

It also happened to be a watershed moment for modern volcanology.

Krakatoa prompted the first modern study of volcanic eruptions, says Nick Petford, a professor of geology and the vice chancellor at the University of Northampton in the UK. Scientists measured the distance from the ocean floor to the surface, a process called depth sounding, to map out the new topography of the destroyed island. They also followed the course of the tsunami across the world's oceans by looking at tide gauges. Finally, they compared barometric measurements from around the world.

"They realized that there were simultaneously huge changes in atmospheric pressure in weather stations around the world," Petford says. They concluded that the blast triggered a pressure wave that circled the globe at least six times.

See the light

Despite the aging technology on Mount Rainier's slopes, the mountain is better monitored than Glacier Peak, whose remote ridgeline I can barely make out to the north from the seismology station I'm visiting. According to The Seattle Times, settlers didn't realize it was a volcano until the 1850s, when Native Americans told naturalist George Gibbs about a mountain that once smoked.

Difficult to reach by roads that are often washed out, Glacier Peak has only one seismology station on it, while Rainier has eight.

That's where lidar (light detection and ranging) comes in. The US Geological Survey and US Forest Service funded an effort to take lidar pictures from cameras mounted on an airplane to reveal what Glacier Peak looks like under its cloak of vegetation. With the mountain's contours plainly visible, the USGS can pinpoint the best areas to take seismic measurements. It's hoping to install four new seismology stations on Glacier Peak's slopes.

Washington State Department of Natural Resources

Drones equipped with mass spectrometers could also prove useful for predicting eruptions.

Nearly 1,100 miles away from Mount Rainier, volcanologists at JPL in Pasadena, California, are developing tiny mass spectrometers -- which can detect gases as they move through sunlight -- that can be mounted on drones.

These devices work because volcanoes emit certain gases in a specific order before an eruption, in a process that begins years before magma reaches the surface. An increase in carbon dioxide means you have potentially months before an eruption, says JPL's Pieri. If it's sulfur dioxide?

"Then you're looking at an imminent eruption," he says.

Three years ago, scientists from the University of Costa Rica flew a fixed-wing drone carrying a small mass spectrometer at Turrialba Volcano, in central Costa Rica while Turrialba was in the middle of erupting, emitting a plume of ash. They've also flown eight-rotor drones with 6-kilogram (13-pound) mass spectrometers over Vulcano, a small Italian island near Sicily, and the crater of Solfatara, near Naples. In partnership with the volcanologists in Costa Rica, Pieri's colleagues at JPL hope to create a mass spectrometer weighing as little as 3 kilograms (6.6 pounds).

The close range data gathered by drones complements imaging NASA has been gathering from a device on its Terra satellite since 2000. The images help scientists measure variations in gasses and temperatures at volcanoes around the world, helping to identify the warning signs of rising magma.

Drones and satellites have a big advantage over backpacks. People don't have to carry them into danger zones.

"One of the reasons we're motivated to use these drones is because a lot of these observations are made by people on the ground, and they get killed," says Pieri. That's not a theoretical risk to Pieri.

He thinks of David Johnston, the 30-year-old volcanologist killed while manning an observation post 6 miles from Mount St. Helens.

"This is like standing next to a dynamite keg and the fuse is lit, but you don't know how long the fuse lasts," Johnston told the AP news service in March 1980, two months before the mountain's eruption (5 on the VEI scale). Johnston is credited with saving lives by closing off the area after detecting signs Mount St. Helens was poised to blow.

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Since then, teams of scientists and engineers have been working diligently to come up with new ways to warn some of the populated areas that have sprung up in these explosive mountains' deadly shadows. But there'll always be unpleasant surprises.

"Most volcanoes are unmonitored," Pieri tells me.

I know we'll be lucky to get any warning at all if that gorgeous time bomb I grew up near ever blows its top. So I try to stay optimistic and hope science and technology will find more ways to keep us safe when the Earth decides it's had enough.

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