When a dangerous landslide hits, rescuers scrambling to assist need to know exactly where to look – and now a new technique for analysing seismic data can do just that, by tracing the source of the disaster to within a few kilometres in mere seconds.

Existing methods can only narrow down locations to within tens of kilometres, says at the Helmholtz Centre for Geosciences in Germany. In remote areas, this can lead to delays if rescuers are sent to the wrong place. “That time loss can be crucial,” Ursica told a press conference at a meeting of the European Geosciences Union in Vienna last week.

Many countries have a network of seismic monitors to record activity related to earthquakes and volcanoes. This data can also be used to detect events such as landslides – the risk of which is increasing due to climate change – but the data from these kinds of events is much messier and harder to analyse than that from earthquakes, says Ursica.

There are two novel aspects to her team’s approach, she says. The first is to analyse five different aspects of the seismic waveform to pick out from the noise exactly when an event occurred.

This information is then fed to a dozen or so mathematical agents that search for the location of the event, such as the initial rockfall leading to a landslide. They do this by estimating what waveform would have been produced if the event had happened in a particular spot and comparing it to the recorded waveform. If it doesn’t match, they try a different spot.

Each agent “moves” in a pattern inspired by the behaviour of animals, from the spiralling of a falcon to the long migrations of elephants, until they have collectively homed in on the most likely location of the event. The entire process takes only around 10 seconds and is much more accurate than previous approaches. “We have basically an order of magnitude [of] improvement,” Ursica says.

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In addition to helping rescue efforts, it will help researchers locate events in remote areas where satellite data is unclear or unavailable, she says: “We can pinpoint events that we otherwise couldn’t see.”

The team plans to publish the details soon and make the code available for others’ use.

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A children’s hospital that lost access to water in the wake of Hurricane Milton is now using a device that can collect drinking water directly from the air, in a test of how such atmospheric water harvesting systems could be used to respond to disasters.

“When a hospital has both water and power you’re good,” says at Genesis Systems, the Florida-based company that designed the apparatus. The system uses absorbent materials called metal organic frameworks to concentrate moisture from air pumped through the machine, then releases pure water when the material is heated by around 8°C.

Such atmospheric water harvesting systems have long attracted interest because of their ability to operate independently of other water infrastructure. A small but growing number are installed to supply daily water to off-grid communities, and they have been used in cities with poor water infrastructure or arid places where water supplies are unreliable, as well as for military operations. An Arizona-based company called Source that makes solar-powered “hydropanels” has even started selling its air water in cans.

Another way these flexible systems have been used is to respond to disasters that leave communities without a reliable clean water supply. As Hurricane Milton approached Florida’s west coast, , the secretary of the Florida Agency for ��ҹ����1000���� Care Administration, saw an opportunity to try this out.

With Hurricane Ian in 2022, Weida saw how water issues and power outages required some hospitals to close for weeks, with evacuation sometimes required days after the storm itself had passed. He learned about Genesis Systems’ technology while touring damage from Hurricane Helene, which made landfall on 26 September. “I thought, “Wouldn’t this be great for next year’s hurricane season?” he says. “Little did I know that two weeks later we would be preparing for Hurricane Milton.”

Ahead of Milton’s landfall on 9 October, the system was brought to a staging ground for the state’s disaster response. Soon after the hurricane passed, a truck brought it to Johns Hopkins All Children’s Hospital in St. Petersburg where leaking water mains had interrupted the hospital’s water supply. Weida says this particular hospital was a priority because of how challenging it would be to evacuate newborns from the hospital’s large neonatal intensive care unit.

On 10 October, workers hooked up the shipping-container sized system to a generator, and it is now producing up to 2000 gallons of drinking water per day while the hospital’s regular water supply is being fully restored. Stuckenberg says the system can operate more or less anywhere humidity is above 10 per cent, although it becomes less efficient as humidity declines. He estimates that the system installed in Florida’s humid air uses about 0.8 kilowatt hours of electricity per gallon of water.

at Virginia Tech questions whether the system really can harvest so much water while using so little energy. He says it may still be useful in an emergency scenario, but without more information about how it works, he is sceptical about its claimed efficiency.

Stuckenberg points to a study that he and his colleagues published in 2022, which . He says the system’s energy requirements are so low because of the way the material they use bonds to water vapour with almost no energy, with most energy used to run fans, pumps and to re-concentrate the absorbent. The 2022 study suggested the system has a theoretical maximum efficiency of just 0.07 kilowatt hours per gallon of water.

In a more general sense, atmospheric water harvesting systems can be an “important tool” for disaster response when water supplies might be offline for an extended period of time, says at Arizona State University, and are well-suited for places with relatively high humidity like Florida. However, he says their reliance on electricity, often from a generator, has been an issue during past disasters.

On 16 September 2023, seismic monitoring stations around the world detected a strange signal that faded over time but remained detectable for nine days.

“We were like, ‘Oh wow, this signal is still coming in. This is completely different to an earthquake’,” says at University College London. “We called it an unidentified seismic object, or USO.”

Hicks and others have now shown that this signal was caused by water sloshing from side to side across the 2.7-kilometre-wide Dickson Fjord in eastern Greenland. This wave was triggered by a massive landslide that resulted in a 110-metre-high tsunami.

Earthquake signals usually last only minutes and are a mix of different frequencies, says Hicks. The USO had a single frequency of around 11 millihertz, meaning it repeated every 90 seconds. Once it became clear that the signal began at the same time as the Greenland landslide, Hicks and his colleagues realised there was probably a connection.

Many objects, such as a bell, will vibrate at a particular resonant frequency if struck. The same is true of bodies of water, from swimming pools to oceans. Disturbances such as earthquakes and winds can set them rocking, generating a kind of standing wave known as a seiche.

Based on its width and depth, the researchers calculated that the resonant frequency of Dickson Fjord is 11 millihertz – matching the signal. What took them much longer to understand is why the fjord kept rocking for so long.

Immediately after the tsunami, the seiche was going up 7 metres on either side of the fjord. Within days, it had gone down to a few centimetres – so small that a Danish naval boat that went up the fjord three days after the landslide didn’t notice it.

But the seiche just kept going, and it probably persisted long after the nine days, when it was no longer detectable by distant seismic stations, says Hicks. “No one has ever reported seiches lasting for so long, or dissipating their energy so slowly.”

The shape of the fjord was a crucial factor, computer modelling by the team shows. The landslide site is 200 kilometres inland, with a glacier blocking one end of the fjord and a sharp bend at the other. The round bottom of the fjord also acted a bit like a rocking chair, allowing the water to move with little resistance.

All these factors resulted in a high degree of energy trapping, says Hicks, instead of the wave rapidly dissipating as usual.

The landslide itself was a direct result of climate change. A steep glacier was helping to hold up a mountainside. As the glacier thinned, it gave way, resulting in an estimated 25 million cubic metres of rock and ice falling into the fjord – the first ever landslide recorded in eastern Greenland.

Nobody was in the area at the time, but cruise ships do go up the fjord. The tsunami destroyed equipment being used to monitor the area, along with two abandoned hunting huts.

As the planet keeps warming, there will be more landslides of this kind, says Hicks, who notes that the findings show climate change is now even affecting the earth below us as well as the atmosphere and oceans. “For the first time, we’re looking down beneath our feet to see some of the catastrophic impacts of climate change,” he says.