Margaret Mangan did not sleep well in the weeks following the Ridgecrest earthquakes. The July quake triggered a swarm of minor aftershocks in the Coso volcanic field, a cluster of lava domes and ash cones at the northern end of the Mojave Desert. And it was Mangan's job to watch over a possible eruption.
For several weeks, she personally monitored thousands of earthquakes through an automated alert system that pinged her phone all the time. Occasionally, she needed to wake a colleague in the middle of the night to make sure the pattern of agitation did not point to increased magma.
California is famous for its earthquakes and catastrophic fires, but they are not our only natural hazards. As head of CalVO, Mangan drew attention to the state's most neglected threats: a dozen restless volcanoes stretching from Medicine lake near the Oregon border to the Salton buttes in the Coachella valley.
"Most people are surprised that there are volcanoes in California," he said. Kari Cooper, geologist at UC Davis. "It's just not on people's radar."
Should be. According to a report released by Mangan and his colleagues this year, the chance of a small to moderate eruption somewhere in the state over the next 30 years is 16% – about the same as an earthquake of 6.7 or greater magnitude. San Andreas's long fault.
These chances "are not something to ignore," she said.
Margaret Mangan, wearing protective gear, collects lava samples during a 1993 eruption of Mt. Kilauea in Hawaii.
(US Geological Survey)
For Mangan, the threat of a volcanic crisis is not merely hypothetical.
She began her career at the USGS Hawaii Volcano Observatory in 1990, as did Mt. Kilauea began paving the town of Kalapana on the Big Island. It was the first time she had seen an eruption with her own eyes.
"For a volcanologist," she said, "it was almost a religious experience."
The event also took home the degree of devastation a volcano can cause – and made her realize how important it is for people living in active volcanic areas to know what could happen. "I saw what it can do to communities," she said, "and the psyche of the people who come across these things."
Mangan came to California in the late 1990s to work in what was then called the Long Valley Volcanic Observatory.
Long Valley is on the east side of the Sierra Nevada – the mountains themselves are the roots of ancient volcanoes – and attracted scientists for good reason: in 1980, just a few days after Mount Washington. St. Helens blew the top, Mammoth Mountain began to show signs of unease. (It eventually settled down, damaging nothing more than real estate.)
The Long Valley research team also monitored other volcanoes in the area, which were equally – if not more – worrying. This included the relatively young Mono craters, which last broke out in the Middle Ages, and Long Valley Caldera, which produced a super-eruption that threw ashes in the southwestern US 760,000 years ago.
Mangan took command of the observatory in 2009. She and her team used seismometers to hear magma rising through the crust and track the rising ground, which can swell as magma begins to accumulate under a volcano. They also measured the volcanic gases that leaked through the air vents over runways about what was happening underground. (The answer is not yet great.)
The eastern mountain range is not the only volcanically active region in the state. Seven other volcanoes made the most recent USGS watch list, including the Cascade Range Lassen peaks and Mt. Shasta in the north (high risk volcanoes); Medicine Lake Volcano, Clear Lake Volcanic Field near Napa, and Salton Buttes (High Risk); and Death Valley Ubehebe Craters and the Coso Volcanic Field (moderate risk).
Mangan proposed bringing them together in a unified California Volcano Observatory and took command when CalVO was inaugurated in 2012.
In this role, she tried to warn people about the dangers of volcanoes while sharing her fascination with them.
"One of the reasons the state is so beautiful is that there are volcanoes here," she said.
Volcanic activity created the columnar basalt of the Devils Postpile near Mammoth Mountain.
(National Park Service)
In 2010, the Icelandic volcano Eyjafjallajökull produced a modest eruption. He released a quarter of the amount of ashes that Mt. St. Helens, causing zero deaths and minimal damage.
But the eruption disrupted European air traffic for a week, trapping millions of passengers, including the mother of an official from the California Governor's Emergency Services Office. This led the agency to realize that the same could happen in California – and that the state was unprepared.
The MODIS instrument on NASA's Terra satellite captured an ash cloud from Iceland's Eyjafjallajokull volcano as it blew across the North Atlantic, disrupting air traffic.
When CalOES asked for help, Mangan was thrilled. It was exactly the kind of thing she created CalVO to do.
In the following years, she led a team that assessed the California volcanoes and the dangers they pose. The analysis contained some worrying results.
About 200,000 people live daily or visit the state's volcanic risk zones, and 45,000 are close enough to be exposed to threats such as deadly explosions of hot gas and rock, lava flows and volcanic landslides.
Unlike earthquakes, which end in a matter of seconds, volcanic eruptions could drag on, he said. Marcus Bursik, Buffalo University geologist who worked extensively in California. "They persist for a long time – over years, if not decades."
Like Eyjafjallajökull, even a small paroxysm could growl in air travel. Airplanes fly regularly over California volcanoes, carrying up to 300,000 passengers to, from and along the west coast every day. Each year, millions of people pass through Mt. Shasta Hazard Zone on Interstate 5, between Redding and the Oregon Border.
Lake Shasta is an important storage reservoir located in Mt. Shasta Volcanic ash can contaminate water and damage hydroelectric turbines.
(Kent Nishimura / Los Angeles Times)
The indirect effects of an eruption can spread even further, Mangan and his colleagues found.
Thousands of kilometers of high-voltage power lines to major population centers cross risk zones, particularly in the northern part of the state. This could cause a short circuit if covered with damp ash, leaving residents in the dark for weeks.
A pipeline winds through Shasta, Lassen and Medicine Lake, supplying 4.2 million homes. And many of the state's water reservoirs are within the ashfall zones of several volcanoes, the report noted.
"Even a small eruption in the wrong place can span large areas of California's infrastructure and really cause problems for people hundreds of miles away," Cooper said.
Margaret Mangan, in detail at the USGS Alaska Volcano Observatory, briefs the media during a 2009 eruption of Alaska's Redoubt volcano.
(US Geological Survey)
The California Office of Emergency Services is now developing volcano response plans for the state and its vulnerable cities and counties.
"A lot of this is getting out of the way," said Kevin Miller, manager of the CalOES earthquake, tsunami and volcano program.
Many communities are already working on forest fire evacuation procedures, and they can be used in a volcanic crisis, emergency managers say. For example, Siskiyou County – home of Mt. Shasta – coordinated the California Highway Patrol in a plan to command both directions on I-5 if necessary.
CalOES is adding volcanoes to its MyHazards Website, which allows residents to enter their addresses and get information about local threats, as well as advice on how to deal with them.
Communities can also increase resilience by strengthening critical equipment such as power substations with protective shields and closing air vents to keep ashes away from buildings.
These efforts build on the foundations Mangan has laid in recent years. She crossed the state, meeting with local officials to help them understand what a backyard eruption really meant.
At one stop, she convinced Frank Frievalt to consider stronger safeguards for Mammoth Lakes, where he is the head of the fire protection district.
As ash can damage electronics and interfere with radio signals, Frievalt realized that a priority would be to bring extra repeaters. "This happens all the time in forest fires," he said. "In that case, we would have to figure out a way to make them more resilient to an ash environment."
Mangan has also worked with the Federal Emergency Management Agency to develop a California-specific version of its volcano crisis awareness training, which includes a mock eruption exercise.
Chile's Chaitén volcano had been dormant for thousands of years before erupting in May 2008, forcing residents to evacuate.
In 2015, Mangan coordinated an exchange between scientists, emergency responders, and land managers in California and Chile so they could learn from each other about the challenges of living in the shadow of active volcanoes. On their trip, Californians witnessed the aftermath of an eruption in the city of Chaitén, where a volcano roared to life in 2008 and unleashed a stream of mud that buried houses to the windowsill.
"I've never been in a totally decimated place," he said. Carolyn Napper, a Shasta-Trinity National Forest Ranger who participated in the program.
Lassen Volcanic National Park, as seen in 1915, …