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If you felt the ground starting to shake, would you know what you’re supposed to do?
You should. You might be more vulnerable to an earthquake than you realize: According to the US Geological Survey, almost 75 percent of the US population lives in an area that could experience a damaging quake.
Right now, we get scarily little notice before the ground below starts to tremble. Earthquakes create a potent threat even in places that are well prepared — and they’ve proven catastrophic in places that aren’t. One of the deadliest disasters of the 21st century is the January 12, 2010, 7.0 magnitude earthquake in Haiti, which killed more than 220,000 people, with some estimates topping 300,000. Another is the magnitude 9.1 earthquake and ensuing tsunami on December 26, 2004, which claimed about 230,000 lives. As populations grow in seismically active areas, many more people will be at risk.
The World Meteorological Organization observed that between 1970 and 2019, the number of disasters, mostly related to weather, increased fivefold, but deaths fell by two-thirds. Even as climate change worsens downpours, floods, fires, and heat waves, improvements in weather forecasting, longer lead times for warnings, more resilient infrastructure, and better responses in the aftermath have continued to save more lives.
Yet for earthquakes, progress has been much slower. They’re a stubborn outlier in a decades-long downward trend in disaster fatalities, and recent events have shown just how deadly they can be.
A series of three magnitude 6.3 earthquakes in Afghanistan in October 2023 caused almost 1,500 deaths. On September 8, 2023, a magnitude 6.8 earthquake struck Morocco and killed almost 3,000 people. A series of earthquakes beginning with a massive 7.8 magnitude quake across Turkey and Syria on February 6, 2023, claimed more than 55,000 lives.
But there are ways to save lives, and Japan presents an important example.
On New Year’s Day 2024, a powerful magnitude 7.6 temblor rocked the Noto Peninsula in western Japan, damaging more than 76,000 homes and killing around 245 people. It was the deadliest earthquake to hit the country since 2016 and the strongest since 2011.
Japan has a long history of earthquakes, and while the Noto quake was unusually deadly, it could have been far worse without the national automatic early warning system the country launched in 2007 and has refined based on lessons from subsequent geological disasters.
Taiwan also experienced a major earthquake this year. A magnitude 7.4 quake rocked the region on April 3. It was Taiwan’s strongest one in 25 years, yet it killed just around 17 people across the densely populated island. Compare that to the magnitude 7.3 earthquake in Taiwan on September 21, 1999, which killed 2,415 people. In the intervening years, Taiwan upgraded its building codes but also built an early-warning network that scientists credited with keeping the recent casualty count down.
The challenge now is to deploy similar systems around the world, particularly in other earthquake-prone regions.
The United Nations is aiming to cover the whole world with disaster early-warning systems by 2027, a $3.1 billion campaign. Not specifically tied to earthquakes, the warning systems are meant to raise the alarm for multiple hazards.
Scientists, meanwhile, are honing their tools further, racing to detect tiny tremors that could indicate massive movements of the Earth and get warnings out ahead of seismic waves, which travel at thousands of miles per hour. By some estimates, earthquake early warnings could avert up to half of the injuries these disasters typically cause.
These tactics are expensive, the improvements have been small, and some of the most vulnerable parts of the world still lack the resources to deploy them. But given the destructive scale of these violent shudders across the Earth, even small gains could translate to hundreds, if not thousands, of avoided deaths, and the lessons learned from earthquakes could save thousands of lives across all types of catastrophes.
Why it’s so hard to see an earthquake coming
The recent Noto quake permanently reshaped Japan’s coast, lifting the land in the area as much as 13 feet and moving the coastline as much as 800 feet. It’s a small sign at the surface of the powerful forces roiling miles below. The Earth’s tectonic plates slowly jostle each other over millions of years, drifting, slipping, and colliding. As they shift, they create mountains and valleys and build up extraordinary forces that can explosively release in a few seconds, knocking over towering buildings and resculpting the landscape.
Why is it so hard to see these massive movements coming? It turns out that the wide span of timescales involved — from millennia to moments — makes it hard to predict earthquakes in a useful way.
James Goltz, a researcher studying earthquake warnings at the University of Colorado Boulder and a guest scholar at Kyoto University, explained that there are three basic ways that scientists try to gain an advantage against earthquakes.
The first and most robust is long-term forecasting. Using historical data on Earth’s movements and maps of fault lines, researchers can anticipate where quakes are likely to occur, but not necessarily when.
Although geologists can estimate how frequently a major earthquake strikes a region, these recurrence intervals are often measured in centuries, if not longer. Being able to forecast that a major earthquake will occur in a given year, let alone on a specific day, is almost certainly out of the question. A warning that a major quake is likely to occur in a region in the next 500 years can be useful for designing building codes or constructing highways, but such an assessment doesn’t help much if you’re trying to plan an escape route.
The next tactic is short-term forecasting. “That’s something that is relatively new and controversial,” Goltz said. This is where scientists try to use more recent and more subtle shifts in the Earth to predict a larger quake. Smaller tremors sometimes precede larger earthquakes, so researchers are examining what kinds of warning signs have occurred ahead of past disasters to develop criteria for predicting the next one, ideally several days in advance.
But sometimes small tremors are just small tremors, and sorting out which ones herald a disaster is dicey.
This remains an active area of research, but the risks are difficult to communicate to the public, and the stakes are high. In 2012, six scientists received jail sentences for their assessment that a major earthquake was unlikely after a series of tremors rocked L’Aquila, Italy, in 2009. A major earthquake struck days later, on April 6, 2009, killing 309 people. The Italian supreme court later overturned the verdict.
“We can’t ignore a possible foreshock because of the consequences,” Goltz said. “On the other hand, we sometimes feel that this is too low a probability to be actionable, and [forecasters] really don’t want to put themselves out on the limb saying we feel like there’s some caution warranted because of this particular earthquake.”
If a warning system sends out too many alerts, that could inure people to hearing them and result in complacency when a major earthquake does occur.
How a few extra seconds could save scores of lives
The third major way to gain a lifesaving advantage over an earthquake is to issue alerts once a quake has already begun.
“Earthquake early warning is an innovation in itself in the sense that it doesn’t know anything about the earthquake at all until the seismic waves have reached the surface,” said Robert-Michael de Groot, who leads public outreach for the US Geological Survey’s ShakeAlert earthquake early warning system. The goal is not to predict a quake but to respond fast enough to provide useful information.
In this regard, the US is behind Japan. ShakeAlert first launched in 2019 in California and today only covers part of the country. It serves 50 million people in California, Oregon, and Washington — some of the most seismically active states in the US — but leaves out other earthquake-prone states like Alaska and Hawaii.
It works in a similar way to Japan’s early warning system, however. ShakeAlert is building a network of almost 1,700 stations and is 90 percent of the way there, according to de Groot. They’re spread out over a wide area to monitor ground movements, sending signals — sometimes just one second’s worth — to data processing centers that analyze them to model the shape, direction, and magnitude of a quake, filtering the trivial from the significant.
“Most earthquakes happen very fast. Most earthquakes we experience are very small,” de Groot said. “We have 20 to 30 earthquakes every day here in Southern California, and most of them we don’t feel.”
If the signals portend a large quake, the system can send out alerts to cell phones and public address systems as well as trigger a cascade of automatic actions, like slowing down trains, opening valves on water pipes, and closing fire doors in some buildings.
“We rely on ultra-fast detection, telemetry, and processing, all taking just a matter of seconds,” de Groot said. “Seismic waves travel at 13,000 miles per hour, so it’s a race against time.”
This still doesn’t buy people directly above the epicenter much time to react — a few seconds, if they can even get an alert at all. But for people farther away, it can provide valuable time to seek shelter. The challenge here is making sure people know what to do: drop, cover, and hold on. Even if you receive an alert after the shaking arrives, it could signal that an even larger rumble is on its way.
“We always tell people that ShakeAlert is not going to take away the need for you to respond to shaking,” de Groot said. “If you feel sort of that early jiggle, jiggle, jiggle that happens, hopefully that gets you to take protective actions, but what we really are concerned about is making sure you get the alert before the damaging shaking — the shaking that could potentially harm you — occurs.”
Many countries could learn a lot from Japan
Japan’s earthquake detection and warning network was put to the test during the January Noto earthquake. The quake was triggered 6 miles underground, which is considered to be fairly shallow, and left little time for warning systems to kick in.
Earthquakes typically generate two distinct modes of movement. After the initial rumbles begin, a second, slower-moving wave ripples out from the epicenter, causing the ground to oscillate up and down and forming the more destructive phase of the quake.
The Japan Meteorological Agency, which handles earthquake warnings, sent its first alert across the Noto region 6 seconds after it observed the first wave. For people living within a radius of about 12 to 18 miles, those early warnings on their cell phones, radios, and neighborhood PA systems didn’t arrive until they could already feel the more damaging second wave, but they still bought valuable time ahead of larger shocks.
“This particular earthquake, we actually had two earthquakes in a very short time,” Masumi Yamada, an associate professor in the Disaster Prevention Research Institute at Kyoto University told Vox. “At the beginning it was small, and then it got larger and larger and larger.”
But Yamada noted that some uncommon factors also exacerbated the death toll from the earthquake beyond its raw strength and despite the early warnings.
While the Noto Peninsula is more sparsely populated than the metropolises on the other side of Japan’s main island, the quake occurred on New Year’s Day, which is a major holiday and a time when families gather, so people were congregating at home when the tremors began. The demographics of the region are older than the average in Japan, and so is the housing stock, with many homes not up to the latest earthquake resistance codes. More than 76,000 homes were damaged that day, and 90 percent of deaths were caused by falling buildings. Sixty percent of deaths were among people in their 70s or older.
It was also a very cold day. At least 32 people died from hypothermia or other cold-related causes after the quake. And during the harried response, a Japan Coast Guard plane carrying relief supplies for earthquake survivors collided with a commercial airliner, killing five of the six coast guard crew members.
The efforts to reduce earthquake casualties thus cannot start and end with the shaking earth. It requires a holistic approach, ranging from restricting where people are allowed to build in the first place to implementing strategies to reduce injuries from rubble, broken gas pipes, and downed power lines in the aftermath. As Japan has learned, saving lives requires public education as well, including disaster drills and established evacuation routes.
For other countries aiming to emulate this kind of system, Yamada said that in addition to deploying a seismic sensor network, earthquake early warning systems also need robust high-speed data networks to prevent bottlenecks. “Those kinds of things will happen when a big event occurs and there’s an increase of data and the system slows down,” she said.
It won’t be quick, easy, or cheap, but early warnings could prove to be the most effective way to contain an earthquake’s devastation, and the lessons could also reduce the toll of every type of catastrophic natural disaster that humanity faces.
