Advancing earthquake prediction with an unmanned aerial vehicle

Institute of Industrial Science, The University of Tokyo

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For the first time, researchers at Institute of Industrial Science, The University of Tokyo, quickly and efficiently measure the seafloor down to the centimeter-level using an unmanned aerial vehicle 

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Credit: Institute of Industrial Science, The University of Tokyo

Tokyo, Japan - Megathrust earthquakes are large earthquakes that occur on faults found along the boundaries between tectonic plates. The Nankai Trough is a megathrust earthquake zone lying off the southwestern coast of Japan, and experts estimate that this zone could generate a potentially devastating (magnitude 8 or 9) large earthquake sometime in the next 30 years. In addition to the direct catastrophic impact of such powerful ground shaking, a seismic event of this magnitude could trigger cascading hazards such as destructive tsunamis.

Developing the technologies for efficient and reliable seafloor monitoring is paramount when considering the potential for socioeconomic harm represented by megathrust earthquakes. Traditionally, seafloor measurements have been obtained using transponder stations located on the seafloor that communicate with satellites via buoys or ocean-going vessels to produce accurate positional information. However, data collection using such systems has problems such as low efficiency and speed.

In a study published in Earth and Space Science, researchers at Institute of Industrial Science, The University of Tokyo, addressed the challenge of acquiring reliable, high-precision, real-time seafloor measurements by constructing a seaplane-type unmanned aerial vehicle (UAV) that can withstand ocean currents and wind. This vehicle is intended for use with the Global Navigation Satellite System–Acoustic (GNSS-A)―a system that uses satellites to determine locations on Earth―to provide a communication link with seafloor transponder stations.

“We conducted initial experiments in a water tank,” explains lead author of the study Yuto Yoshizumi, “and found that the proposed system can detect distances to an accuracy within 2.1 cm.”

To further evaluate the system, at-sea trial tests were performed by landing the UAV on the sea surface off the coast of Japan under optimal sea conditions. “The results were hugely encouraging,” says senior author Yusuke Yokota. “These seafloor positioning measurements are the first ever achieved using a UAV, and we attained a horizontal root mean square error of approximately 1–2 cm, which is easily comparable to that of existing vessel-based systems.”

The rapid real-time acquisition of seafloor information using the UAV system developed by the research team at Institute of Industrial Science, The University of Tokyo, is expected to provide the foundation for advanced research into earthquake disaster prevention. Such data are urgently needed given the speed and frequency of occurrence of megathrust earthquakes on the Nankai Trough.

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The article, “Construction and Demonstration of a Seaplane-type UAV-based High-Precision GNSS-A Seafloor Crustal Deformation Observation System,” was published in Earth and Space Science at DOI: <a href="https://doi.org/10.1029/2025EA004237" target="_blank">10.1029/2025EA004237</a>.

 

About Institute of Industrial Science, The University of Tokyo

The Institute of Industrial Science, The University of Tokyo (UTokyo-IIS) is one of the largest university-attached research institutes in Japan. UTokyo-IIS is comprised of over 120 research laboratories—each headed by a faculty member—and has over 1,200 members (approximately 400 staff and 800 students) actively engaged in education and research. Its activities cover almost all areas of engineering. Since its foundation in 1949, UTokyo-IIS has worked to bridge the huge gaps that exist between academic disciplines and real-world applications.

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Journal

Earth and Space Science

DOI

10.1029/2025EA004237 

Article Title

Construction and Demonstration of a Seaplane-type UAV-based High-Precision GNSS-A Seafloor Crustal Deformation Observation System

Article Publication Date

23-Jul-2025

 

Spying on stingrays: first-ever tags reveal elusive behaviors and habitats

Florida Atlantic University

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Researchers captured the feeding behavior of a whitespotted eagle ray with video and acoustics.

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Credit: Cecilia Hampton, FAU Harbor Branch

Biologging – an innovative, non-invasive method of tracking animals in the wild – is transforming how scientists study movement, behavior and social interactions. Using compact electronic devices that can remain attached for hours or even months, researchers can now gather detailed data with minimal disruption to the animals’ natural lives.

Although biologging has been widely applied to marine mammals such as turtles and sharks, skates and stingrays (batoids) have been overlooked. This oversight is concerning, as many batoid species are increasingly at risk of extinction yet play critical roles in marine food webs. However, their behavior remains poorly understood – largely because studying them in the wild has been so challenging. For example, one major challenge is their unique body shape: unlike sharks, rays lack a prominent dorsal fin, and some species have ultra-smooth skin, making it difficult to attach tracking devices securely.

Researchers from Florida Atlantic University’s Harbor Branch Oceanographic Institute are the first to successfully develop and field-test a multi-sensor biologging tag on the elusive whitespotted eagle ray (Aetobatus narinari), a species found in tropical and subtropical coastal waters.

Feeding primarily on hard-shelled prey such as clams and conch, this large, powerful predator can grow more than 2 meters (6.5 feet) in wingspan and weigh several hundred kilograms. Although known for long-distance migrations, they often linger in coastal habitats and lagoons, making them an ideal candidate to test the new biologging technology.

The study findings, published in the journal Animal Biotelemetry, demonstrate that the tag’s innovative design enabled it to remain securely attached even in strong currents. This resulted in the longest documented attachment times for external tags on pelagic rays – lasting up to 60 hours. This is the first time a biologging system like this has been successfully used on a stingray species that feeds on hard-shelled prey.

“These animals are powerful, fast-moving and live in dynamic, high-energy environments, which makes tagging them a real challenge,” said Matt Ajemian, Ph.D., senior author, an associate research professor and director of the Fisheries Ecology and Conservation Lab (FEC) at FAU Harbor Branch. “Our goal was to create a system that could be applied in seconds, stay on during natural behaviors, and collect rich, multi-dimensional data. We’re now able to observe not just where these rays go, but how they feed, how they move through their habitats, and how they interact with other species – insights that were virtually impossible to capture before.”

The custom-built tag integrates a motion sensor, video camera, underwater microphone, satellite transmitter and acoustic tracker – all within a compact, lightweight design. These tags are engineered to capture detailed feeding behaviors, with particular attention to interactions involving armored prey.

A key innovation is the fast, minimally-invasive attachment system, which uses silicone suction cups and specially designed straps secured near the ray’s spiracles (the small openings just behind the eyes). The design and implementation of the spiracle straps significantly increased retention and is likely applicable to other similar species of rays.  

“Our work marks a turning point in how we study elusive marine species like pelagic rays,” said Cecilia M. Hampton, corresponding author and a Ph.D. student in the FEC lab at FAU Harbor Branch. “We’ve shown that complex behaviors – like the crunching of clams – can be identified using sound and movement data alone, even without video. This opens up exciting possibilities for long-term ecological monitoring using simpler, more efficient tags. It’s not just about observing feeding – we’re beginning to map out entire behavioral landscapes, from foraging strategies to social dynamics. These insights are vital for understanding how rays respond to environmental change and how best to protect them.”

To pinpoint key movement signals that predict these behaviors, researchers used a supervised machine learning method called a Random Forest model. They trained the model on data from one tagged ray, with two reviewers first labeling behaviors – “swimming,” “browsing” and “digging” – by reviewing video footage. The model predicted foraging behavior well, which paves the way for more accessible and smaller tags to be used in the future for the same performance. More data from varied locations will help further develop these relationships.

Looking ahead, the researchers say their tagging system could be adapted to other ray species, with slight modifications to account for differences in body size and spiracle shape.

“As biologging technologies advance, combining data streams like movement, sound and video – and applying machine learning for behavior classification – could turn rays into mobile surveyors of ocean health and benthic habitats,” Ajemian said.

Study co-authors are Breanna C. DeGroot, State College of Florida; Lauran Brewster, Ph.D., School for Marine Science & Technology, University of Massachusetts, Dartmouth; Kim Bassos-Hull, Ph.D., Sharks & Rays Conservation Program, Mote Marine Laboratory; Benjamin A. Metzger, FAU Harbor Branch; and T. Aran Mooney, Biology Department, Woods Hole Oceanographic Institute. 

This work was supported by the National Science Foundation and Harbor Branch Oceanographic Institute Foundation.

- FAU -

Spying on Stingrays - Multi-sensor Tag [VIDEO] | 

Researchers placed a multi-sensor tag on a whitespotted eagle ray and captured where they go, how they feed, how they move through their habitats, and how they interact with other species – insights that were virtually impossible to capture before.

Credit   FAU Harbor Branch and Kyle Newton

A whitespotted eagle ray swims with the multi-sensor tag.

Credit
FAU Harbor Branch

Researchers place the multi-sensor tag on a whitespotted eagle ray.

Credit
Kyle Newton




Cecilia M. Hampton places a multi-sensor tag on a whitespotted eagle ray.

Credit
FAU Harbor Branch




Close-up of the multi-sensor tag on a whitespotted eagle ray.

Credit
FAU Harbor Branch




Researchers release a whitespotted eagle ray fitted with the multi-sensor tag.

Credit
Kyle Newton

About Harbor Branch Oceanographic Institute:
Founded in 1971, Harbor Branch Oceanographic Institute at Florida Atlantic University is a research community of marine scientists, engineers, educators, and other professionals focused on Ocean Science for a Better World. The institute drives innovation in ocean engineering, at-sea operations, drug discovery and biotechnology from the oceans, coastal ecology and conservation, marine mammal research and conservation, aquaculture, ocean observing systems and marine education. For more information, visit www.fau.edu/hboi.

 

About Florida Atlantic University:
Florida Atlantic University, established in 1961, officially opened its doors in 1964 as the fifth public university in Florida. Today, Florida Atlantic serves more than 30,000 undergraduate and graduate students across six campuses located along the Southeast Florida coast. In recent years, the University has doubled its research expenditures and outpaced its peers in student achievement rates. Through the coexistence of access and excellence, Florida Atlantic embodies an innovative model where traditional achievement gaps vanish. Florida Atlantic is designated as a Hispanic-serving institution, ranked as a top public university by U.S. News & World Report, and holds the designation of “R1: Very High Research Spending and Doctorate Production” by the Carnegie Classification of Institutions of Higher Education. Florida Atlantic shares this status with less than 5% of the nearly 4,000 universities in the United States. For more information, visit www.fau.edu.

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Journal

Animal Biotelemetry

DOI

10.1186/s40317-025-00416-2 

Method of Research

Observational study

Subject of Research

Animals

Article Title

Sticking with it: a multi-sensor tag to reveal the foraging ecology and fine-scale behavior of elusive durophagous stingrays

Article Publication Date

24-Jul-2025

 SPACE/COSMOS

Moon under bombardment

Where does the Moon’s exosphere come from? A TU Wien study using real lunar rock reveals that the erosive effect of solar wind ions on the Moon has been vastly overestimated.

Vienna University of Technology

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Moon rock in a vacuum chamber at TU Wien

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Credit: TU Wien

The Moon’s surface is continuously bombarded by the solar wind – a stream of electrically charged particles ejected by the Sun. These high-energy ions can knock atoms out of the Moon’s uppermost layer of rock, forming an extremely thin envelope of gas around the Moon known as the exosphere. But how exactly this exosphere forms, has remained a major open question.

A research team at TU Wien, in collaboration with international partners, has now demonstrated that one of the key processes – solar wind–driven sputtering – has been significantly overestimated in previous models. The reason: earlier calculations neglected the rough and porous nature of real lunar regolith. For the first time, high-precision experiments using original samples from NASA’s Apollo 16 mission, combined with state-of-the-art 3D modeling, have allowed the team to determine realistic sputtering rates. The results have now been published in the journal Communications Earth & Environment (Nature Portfolio).

A Thin Atmosphere – But Where Does It Come From? 

“The Moon has no dense atmosphere like Earth – but it does have a tenuous exosphere, made up of individual atoms and molecules,” explains Prof. Friedrich Aumayr from the Institute of Applied Physics at TU Wien. “Understanding the origin of these particles remains one of the key questions in lunar science.”

Two mechanisms have been considered as main contributors: either particles are ejected by high-velocity micrometeorite impacts, or they are released via interaction with the solar wind – the constant stream of protons, helium ions, and other charged particles emitted by the Sun. Until now, however, reliable experimental data on actual solar wind sputtering from lunar material has been lacking.

First Experiments with Real Lunar Rock

For the first time, precision experiments have now been performed at TU Wien using original Moon rock from NASA’s Apollo 16 mission. “Using a specially developed quartz crystal microbalance, we were able to measure the mass loss of lunar material due to ion bombardment with extremely high accuracy,” explains Johannes Brötzner, PhD student at TU Wien and lead author of the new publication. “In parallel, we conducted large-scale 3D computer simulations on the Vienna Scientific Cluster, allowing us to incorporate the actual surface geometry and porosity of lunar regolith into our calculations.”

The result: the real erosion rate caused by the solar wind has been drastically overestimated. The actual yield is up to an order of magnitude lower than previously assumed. This is primarily due to the structure of the regolith – a porous, loosely bound layer of dust covering the Moon’s surface. When incoming ions strike the regolith, they often lose their energy in multiple collisions inside microscopic cavities, rather than immediately ejecting surface atoms. As a result, the sputtering efficiency is significantly reduced compared to a smooth, dense surface.

Micrometeorites Outweigh the Solar Wind 

“Our study provides the first realistic, experimentally validated sputtering yields for actual lunar rock,” says Friedrich Aumayr. “Not only does this explain why earlier models overestimated solar wind erosion – it also helps resolve a previously unresolved scientific discrepancy: A recent Science Advances study based on isotope analysis of Apollo samples concluded that, over geological timescales, micrometeorite impacts – not the solar wind – are the dominant source of the lunar exosphere. Our new experimental data independently confirms this conclusion from an entirely different perspective.“

Key Insights for Lunar and Mercury Missions

These results are especially timely: NASA’s Artemis program is advancing in a new era of lunar exploration, and ESA’s and JAXA’s BepiColombo mission is set to deliver the first in-situ measurements of Mercury’s exosphere in the coming years. Interpreting these data will require a detailed understanding of the underlying surface erosion mechanisms – and that is precisely where TU Wien’s research makes a crucial contribution.

The author team from TU Wien: Richard A. Wilhelm, Gyula Nagy, Johannes Brötzner (first author of the study), Martina Fellinger, Friedrich Aumayr (left to right)

Credit

David Rath, TU Wien

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Journal

Communications Earth & Environment

DOI

10.48436/zv721-mkb07 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Solar wind erosion of lunar regolith is suppressed by surface morphology and regolith properties

NASA, JAXA XRISM satellite X-rays Milky Way’s sulfur'

NASA/Goddard Space Flight Center

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This composite shows a section of the interstellar medium scientists X-rayed for sulfur using the Japan-led XRISM (X-ray Imaging and Spectroscopy Mission). X-ray binary GX 340+0 is the blue dot in the center. The composite contains a blend of imagery in X-rays (represented in deep blue), infrared, and light.

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Credit: DSS/DECaPS/eRosita/NASA’s Goddard Space Flight Center

An international team of scientists have provided an unprecedented tally of elemental sulfur spread between the stars using data from the Japan-led XRISM (X-ray Imaging and Spectroscopy Mission) spacecraft.

Astronomers used X-rays from two binary star systems to detect sulfur in the interstellar medium, the gas and dust found in the space between stars. It’s the first direct measurement of both sulfur’s gas and solid phases, a unique capability of X-ray spectroscopy, XRISM’s (pronounced “crism”) primary method of studying the cosmos. 

“Sulfur is important for how cells function in our bodies here on Earth, but we still have a lot of questions about where it’s found out in the universe,” said Lía Corrales, an assistant professor of astronomy at the University of Michigan in Ann Arbor. “Sulfur can easily change from a gas to a solid and back again. The XRISM spacecraft provides the resolution and sensitivity we need to find it in both forms and learn more about where it might be hiding.”

A paper about these results, led by Corrales, published June 27 in the Publications of the Astronomical Society of Japan. 

Using ultraviolet light, researchers have found gaseous sulfur in the space between stars. In denser parts of the interstellar medium, such as the molecular clouds where stars and planets are born, this form of sulfur quickly disappears. 

Scientists assume the sulfur condenses into a solid, either by combining with ice or mixing with other elements. 

When a doctor performs an X-ray here on Earth, they place the patient between an X-ray source and a detector. Bone and tissue absorb different amounts of the light as it travels through the patient's body, creating contrast in the detector.

To study sulfur, Corrales and her team did something similar. 

They picked a portion of the interstellar medium with the right density — not so thin that all the X-rays would pass through unchanged, but also not so dense that they would all be absorbed.

Then the team selected a bright X-ray source behind that section of the medium, a binary star system called GX 340+0 located over 35,000 light-years away in the southern constellation Scorpius. 

Using the Resolve instrument on XRISM, the scientists were able to measure the energy of GX 340+0’s X-rays and determined that sulfur was present not only as a gas, but also as a solid, possibly mixed with iron.

“Chemistry in environments like the interstellar medium is very different from anything we can do on Earth, but we modeled sulfur combined with iron, and it seems to match what we’re seeing with XRISM,” said co-author Elisa Costantini, a senior astronomer at the Space Research Organization Netherlands and the University of Amsterdam. “Our lab has created models for different elements to compare with astronomical data for years. The campaign is ongoing, and soon we’ll have new sulfur measurements to compare with the XRISM data to learn even more.”

Iron-sulfur compounds are often found in meteorites, so scientists have long thought they might be one way sulfur solidifies out of molecular clouds to travel through the universe. 

In their paper, Corrales and her team propose a few compounds that would match XRISM’s observations — pyrrhotite, troilite, and pyrite, which is sometimes called fool’s gold. 

The researchers were also able to use measurements from a second X-ray binary called 4U 1630-472 that helped confirm their findings. 

“NASA’s Chandra X-ray Observatory has previously studied sulfur, but XRISM’s measurements are the most detailed yet,” said Brian Williams, the XRISM project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Since GX 340+0 is on the other side of the galaxy from us, XRISM’s X-ray observations are a unique probe of sulfur in a large section of the Milky Way. There’s still so much to learn about the galaxy we call home.”

XRISM is led by JAXA (Japan Aerospace Exploration Agency) in collaboration with NASA, along with contributions from ESA (European Space Agency). NASA and JAXA developed Resolve, the mission’s microcalorimeter spectrometer.

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Journal

Publications of the Astronomical Society of Japan

DOI

10.1093/pasj/psaf068 

Article Title

XRISM insights for interstellar sulfur

 

Alcohol-related liver disease has more than doubled in the last 20 years

Four high-risk population groups — women, adults 45 and older, those living in poverty and people with metabolic syndrome — are possibly driving this increase

University of Southern California - Health Sciences

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Brian P. Lee, MD, MAS, is a hepatologist and liver transplant specialist with Keck Medicine of USC and principal investigator of the study.

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Credit: Photo courtesy of Brian P. Lee, MD, MAS

LOS ANGELES — Americans who drink heavily are more than twice as likely to develop significant liver disease compared to 20 years ago, according to a new Keck Medicine of USC study published today in Clinical Gastroenterology and Hepatology.  

“Alcohol-related liver disease is the main cause of liver-related death and these results are a major wakeup call to the dangers of drinking,” said Brian P. Lee, MD, MAS, a hepatologist and liver transplant specialist with Keck Medicine and lead author of the study.  

The study also sheds light on the demographics of American drinkers, uncovering that four groups make up a greater share of heavy drinkers than they did 20 years ago — women, adults 45 and older, those living in poverty and people with metabolic syndrome, a cluster of conditions that together raise the risk of coronary heart disease, diabetes and stroke. Previous studies have already associated these groups with a higher risk of liver disease when exposed to alcohol.  

“These findings — the first comprehensive look at the demographics of heavy drinking and their relation to liver disease since the 1990s — provide important new information about which population groups may need more intervention to curb alcohol use and may also explain the rise in liver disease over the years,” said Lee.  

Additionally, the study showed that the average drinking rate in America was unchanged over the last 20 years before the COVID-19 pandemic, suggesting that factors beyond alcohol quantity, such as changing health and demographic profiles, may be contributing to the rise in liver disease.  

“Our results show that the makeup of the American public with heavy alcohol consumption has changed compared to 20 years ago,” said Lee.  

Lee and his fellow researchers analyzed data from the National Health and Nutrition Examination Survey, which assesses the health and nutritional status of adults and children in the United States, from 1999-2020, the most recent year for which complete data was available.  

They tracked the total increase in significant liver disease — a stage of liver disease when the liver forms scar tissue that impairs liver function that is often caused by heavy drinking. The study examined the demographic and health profiles of adults 20 or older who drank heavily. According to the Centers for Disease Control and Prevention, heavy drinking is considered eight drinks per week for women and 15 for men. 

Lee believes that the study results will provide physicians with necessary updates to better treat patients and hopes they will lead to more screenings and interventions for high-risk populations.  

Jennifer Dodge, MPH, assistant professor of research medicine and population and public health sciences with the Keck School of Medicine of USC, was also a study author.  

The study was supported by a grant from the National Institute on Alcohol Abuse and Alcoholism, grant number K23AA029752.  

These findings build on Lee’s previous work, including a February 2025 study that found heavy drinkers with diabetes, high blood pressure or increased waist size had double the risk of advanced liver disease, and a November 2024 study revealing that heavy drinking rose during the COVID-19 pandemic peak and continued for two years afterward. 

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For more information about Keck Medicine of USC, please visit news.KeckMedicine.org. 

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Journal

Clinical Gastroenterology and Hepatology

DOI

10.1016/j.cgh.2025.07.006