Editors’ Vox is a blog from AGU’s Publications Department.
As the AGU Books Program celebrates its 70th anniversary in 2026, we reflect on the longevity of scientific work published in book format and the enduring nature of readership—sometimes for decades after publication. We spoke with Volume Editors and Authors of AGU books published in each of the past 3 decades about why they decided to pursue book projects and why readers are still discovering their work years later.
2000s: Filling
As the AGU Books Program celebrates its 70th anniversary in 2026, we reflect on the longevity of scientific work published in book format and the enduring nature of readership—sometimes for decades after publication. We spoke with Volume Editors and Authors of AGU books published in each of the past 3 decades about why they decided to pursue book projects and why readers are still discovering their work years later.
2000s: Filling Gaps in the Existing Research
Ernie R. Lewis and Stephen E. Schwartz decided to write a book after finding a gap in the literature when conducting their own research. Sea Salt Aerosol Production: Mechanisms, Methods, Measurements, and Models, published in 2004, explores the major influences that sea salt aerosol exerts over diverse areas of geophysics.
Why did you decide to write an AGU monograph?
Sea salt aerosol is the dominant background aerosol in the atmosphere and the topic of Lewis and Schwartz’s 2004 book. Credit: Richard Dorrell, Wikimedia Commons
We were looking for a quality venue for publication that would lend respect to the book and could accommodate many large, complicated color figures, which were essential to the book. AGU’s Geophysical Monograph Series met these requirements.
We had been examining the literature pertinent to the production of sea salt aerosol, the dominant background aerosol in the atmosphere, to develop means of representing it in chemical transport models for aerosol influences on clouds and climate. We found major discrepancies in reported production flux (orders of magnitude) and in its dependence on controlling variables. Ultimately, we decided we needed to write a book dealing with the physical processes and comparing the numerous prior studies.
How has the study of sea salt aerosols evolved since the publication of your book?
This field has grown enormously since publication of the book in 2004, especially with new studies identifying the role of organics affecting production of aerosol particles, particle composition, hygroscopic properties, and rate of exchange of water between gas and condensed phase.
Why do you think your book continues to be of value to readers?
Perhaps the greatest strength of the book is its emphasis on processes and material properties. The chapter on fundamentals is nearly 100 pages; the chapter on measurements and models required to determine production fluxes is nearly 200 pages. The material in these chapters is essential to understanding the governing processes.
We are gratified by the continuing influence of the book, a measure of which is that the book has been cited over a thousand times, with an average annual citation rate of more than 70 over the past several years—some 20 years after publication.
2010s: Finding the Cutting Edge from AGU Events
A successful 2012 AGU Chapman Conference convinced Venkataraman Lakshmi that a book was needed to document key outcomes from the conference. He went on to co-edit Remote Sensing of the Terrestrial Water Cycle, published in 2014, which examines the use of satellite data for quantifying the spatial and temporal variations in the hydrological cycle.
Why did you decide to edit a book?
The reason to edit any book is a lack of content on the subject and that the topic is cutting-edge in the research sphere. All the books I have edited with AGU, including Remote Sensing of the Terrestrial Water Cycle, have been outcomes of either sessions organized at the AGU Annual Meeting or a Chapman Conference. The book then serves as a state-of-science for the community and is still widely read.
AGU Annual Meetings and Chapman Conferences have been integral to Lakshmi’s path as a book editor. Credit: Beth Bagley
How has the field of remote sensing as it relates to the terrestrial water cycle evolved since the publication of your book?
The field of remote sensing of the terrestrial water cycle doubles in knowledge every few years. New Earth observing missions have been launched or will be launched soon, and these missions hold promise for unraveling the mysteries of the hydrological cycle.
Why do you think your book continues to be of value to readers?
The book captures what we can expect from Earth observing missions and sets the stage for how the science questions regarding the water cycle have evolved over the past few decades.
2020s: Building on the Success of Earlier Work
Yongliang Zhang and Larry J. Paxton, from the Johns Hopkins Applied Physics Laboratory, edited not one but five books, published in 2021. This five-volume collection, Space Physics and Aeronomy, presents the latest scientific observations, models, and theories about the Sun and the solar wind, magnetospheres in the solar system, Earth’s ionosphere, Earth’s upper atmosphere, and space weather.
Why did you decide to edit a set of books?
Following a successful AGU 2014 session on auroral dynamics to which about 60 abstracts were submitted, we were invited by editors of three publishers in the United States and Europe to edit a book on auroras. We accepted the invitation from AGU–Wiley as there was a lot of interest in auroral study in the AGU community. We submitted a proposal for a book titled Auroral Dynamics and Space Weather. The book,published in 2015, was successful and a few years later, we were invited to edit multiple books as a major reference work in the field of heliophysics. We took the opportunity and finished the five-book set in 2021.
How have space physics and aeronomy evolved since the publication of your books?
First, new satellite missions and more ground observations are available that fill some of the measurement gaps that existed when we published the books. Second, recent advances in AI capability together with increasing data volume in space physics enable a better specification of the space physics phenomena as well as space weather forecasting.
Why do you think your books continue to be of value to readers?
These five volumes (six, counting Auroral Dynamics and Space Weather) provide, in one set, a detailed overview of the science of the space environment from the Sun to the Earth and its variability, or “space weather.” A series of books like this is invaluable as a survey of real knowledge that provides readers the opportunity to discover new insights in heliophysics.
As of early 2026, two major imperatives that drive NASA research are facilitating the space economy and supporting the Moon to Mars initiative with an emphasis now on supporting the return to the Moon. Heliophysics, the focus of our books, enables the outward journey to near-Earth space, the Moon, and beyond. Scientists at all stages in their careers are sure to find in these six volumes useful insights that they can use to address new NASA funding opportunities.
Heliophysics, the focus of Paxton and Zhang’s set of books, is essential to new NASA missions. A view of Earth taken by NASA astronaut and Artemis II commander Reid Wiseman from the Orion spacecraft in April 2026. Credit: NASA
These three experiences are just a snapshot of the more than 750 volumes published by AGU Books since the 1950s. While the methods and technologies used in scientific research have evolved dramatically, as has the process and formats for publishing books, the need for volumes covering the breadth of Earth and space sciences remains strong. The AGU Books Program has proven that books—whether the outcome of a gap discovered in the literature, a popular conference session, or the success of previous works—have a lasting place in the ecosystem of scientific publishing.
Citation: Liling, D., V. Lakshmi, E. R. Lewis, L. J. Paxton, S. E. Schwartz, and Y. Zhang (2026), 7 decades of books leave a lasting legacy, Eos, 107, https://doi.org/10.1029/2026EO265024. Published on 3 June 2026.
This article does not represent the opinion of AGU, Eos, or any of its affiliates. It is solely the opinion of the author(s).
Source: Earth’s Future
Coastal landscapes are constantly being reshaped by natural forces, and as climate change causes more frequent storms and sea level rise, that change will only intensify. Because these areas are densely populated with homes, tourist destinations, and industries, understanding how and where the coast will change is a pressing issue. However, reliable predictions that lead to actionable knowledge are rare.
Lentz et al. describe the state of knowledge regarding coastal
Coastal landscapes are constantly being reshaped by natural forces, and as climate change causes more frequent storms and sea level rise, that change will only intensify. Because these areas are densely populated with homes, tourist destinations, and industries, understanding how and where the coast will change is a pressing issue. However, reliable predictions that lead to actionable knowledge are rare.
Lentz et al. describe the state of knowledge regarding coastal evolution, highlight gaps in scientists’ understanding, and describe opportunities for integrating information from various models, data sources, and end users.
Current coastal evolution predictions are often focused on too specific a location and are therefore hard to generalize or analyze too large a region and therefore lack detail, the authors say. In addition, it’s challenging for researchers to link the effects of acute events, such as storms, with long-term trends like sea level rise.
Improving these simulations will likely require combining many different types of models, including physics-based numerical models, models based on empirical measurements, and statistical models that include machine learning. To fully understand potential changes, the authors note that it is also essential to consider both coastal processes and human actions.
The researchers recommend several ways to improve consistency and collaboration in the field of coastal change forecasting. First, standardizing approaches and outcomes would make it easier to produce national-scale predictions. Right now, the variety of tools used across different locations makes it difficult for scientists to compare results and communicate effectively. They also emphasize the need for using coordinated research approaches. Stronger transdisciplinary collaboration, accompanied by essential training and support, would also enable scientists to make better predictions, the researchers say.
Comparing predictions to real-world observations of coastal landscape change could also help untangle this multifaceted challenge. By studying how coastlines have already changed, researchers can validate models and choose those that are performing best. Such comparisons require datasets that adequately capture coastal landscape change across both time and space. Remote sensing data and the use of artificial intelligence (AI) for data processing may help provide these improved datasets, the researchers suggest.
Engaging end users during the project planning process is also helpful because only end users truly know what kind of information they need to adapt to landscape change. Knowing how to engage end users can be difficult for physical scientists, but various tools and specialized personnel exist who can help coordinate these interactions, the authors say. (Earth’s Future, https://doi.org/10.1029/2024EF005833, 2026)
When it comes to thriving at high elevation, diminutive plants are always a safe bet. And low-lying vegetation is in fact colonizing higher and higher reaches as the climate changes, new results reveal. Researchers analyzed more than 2 decades’ worth of satellite data and showed that the vegetation line in the Himalayas is moving upward, in some cases by up to several meters per year. These changes have implications for the hydrology of the region and therefore for water resources for the popul
When it comes to thriving at high elevation, diminutive plants are always a safe bet. And low-lying vegetation is in fact colonizing higher and higher reaches as the climate changes, new results reveal. Researchers analyzed more than 2 decades’ worth of satellite data and showed that the vegetation line in the Himalayas is moving upward, in some cases by up to several meters per year. These changes have implications for the hydrology of the region and therefore for water resources for the population centers located downstream, the team reported last month in Ecography.
Mountains and People
“If you’re going to understand climate change across the Himalayas, you can’t just look at one location.”
The Himalayas, with their massive stores of frozen water, are part of a region known as the planet’s “Third Pole.” Nearly a billion people rely on water sourced from this area, but the Himalayas aren’t immune to climate change—shifts in temperature and precipitation patterns are causing glaciers to melt and permafrost to thaw, among other effects. “The Himalayan mountains are experiencing a lot of ecosystem changes,” said Ruolin Leng, an Earth scientist who led this new research while at the University of Exeter in the United Kingdom. She currently works at H2Tab, a wellness company.
And while the macroscopic effects of climate change in mountainous regions—the melting of the aforementioned glaciers, for example—have been readily studied, shifts in vegetation are often overlooked, said Leng. That’s a problem because plant cover affects everything from soil moisture levels to water runoff to the albedo of the planet’s surface, all of which have consequences for how water moves through the larger system, she said. “It’s a very important factor in the hydrological system.”
Leng and her colleagues focused on six sites, each roughly 40,000 square kilometers in size, in Bhutan, Nepal, and politically disputed areas farther west. Altogether the locales spanned roughly 15° in longitude (about the width of a U.S. time zone). The choice to analyze several locations along an east-west gradient was deliberate, said Stephan Harrison, a climate scientist also at the University of Exeter and a member of the research team. “The western Himalayas are very different from the eastern Himalayas in terms of climate. If you’re going to understand climate change across the Himalayas, you can’t just look at one location.”
Spotting Vegetation from Space
For each of those sites, the researchers mined satellite observations collected from 1999 to 2022 by the NASA/U.S. Geological Survey Landsat program. The researchers focused on visible and near-infrared observations to calculate a metric known as the normalized difference vegetation index (NDVI). Vegetation tends to reflect relatively little visible light while reflecting much more near-infrared light, and that fact can be exploited to infer the presence of vegetation in remote sensing data, said Karen Anderson, a remote sensing scientist at the Environment and Sustainability Institute at the University of Exeter and a member of the research team.
After masking out pixels too obscured by clouds or snow to correctly analyze, Leng and her colleagues calculated the NDVI for each 30- × 30-meter Landsat pixel within their study regions. The team retained pixels with NDVI levels above a minimum threshold and used those data, combined with topography information, to estimate the maximum elevation that was reliably vegetated each year. All six sites exhibited upward trends in the elevations of their vegetation lines over time, the researchers found. A site in central Nepal straddling the country’s northern border recorded the largest changes: From 1999 to 2022, the elevation of its vegetation line rose from roughly 5,520 meters to 5,670 meters, an increase of just under 7 meters per year on average. The five remaining sites all recorded annual upward shifts ranging from about 1 to 6 meters per year on average.
“Broadly speaking, plants are moving up mountains,” said Anderson. But different regions are responding differently, she added. (And while similar results have been previously noted in the Himalayas, not all plant life everywhere is moving up—recent research has shown that some tree lines are in fact moving downslope.)
A Climatic Culprit?
“People neglect the little plants.”
To investigate the potential drivers behind these changes, the team studied correlations with three climatic parameters: temperature, total precipitation, and snow depth. These data came from the European Centre for Medium-Range Weather Forecasts reanalysis dataset, which has a spatial resolution of roughly 30 kilometers.
Leng and her collaborators found that their site with the fastest-changing vegetation line also recorded the most rapid increase in snow depth over time. These two changes might therefore be linked, but more work is needed, Anderson admitted. “We haven’t addressed the causal link here. We’ve simply looked for patterns.”
There’s also a significant mismatch in the spatial resolution of the team’s meteorological data and their Landsat data, said Trevor Keenan, an ecosystem scientist at the University of California, Berkeley not involved in the research. Such a discrepancy can be particularly problematic in complex landscapes like mountain ranges because the coarse meteorological data might not be capturing the true microclimates that are bound to persist in such places, he said. “With heterogenous terrain and large elevational gradients, you really need that microclimate information.”
Sagarmatha National Park in Nepal, home to Mount Everest, is also host to rhododendron forests like this one. Credit: Peter Prokosch, CC BY-NC-SA 2.0
Anderson knows the geographical complexity of the Himalayas firsthand—in 2017 and 2022, she and other scientists conducted fieldwork in Nepal that informed this research. Those trips were a special opportunity to see plants like dwarf rhododendron thriving in tough conditions, she said. And it was a good lesson in appreciating some of the most diminutive members of the plant kingdom, Anderson added. “People neglect the little plants.”
Thirty years ago, the blockbuster movie Twister featured a group of academics putting themselves at risk by chasing tornadoes in the name of science. Although the Hollywood story entailed a surfeit of sensationalism, special effects, and unrealistic stereotypes, the movie got a few things right. Specifically, the scientists were trying to study tornadoes using a large number of spatially distributed, home-built, low-cost (and potentially sacrificial) sensors.
Today, we commonly refer to the
Thirty years ago, the blockbuster movie Twister featured a group of academics putting themselves at risk by chasing tornadoes in the name of science. Although the Hollywood story entailed a surfeit of sensationalism, special effects, and unrealistic stereotypes, the movie got a few things right. Specifically, the scientists were trying to study tornadoes using a large number of spatially distributed, home-built, low-cost (and potentially sacrificial) sensors.
Today, we commonly refer to the coordinated use of tens to hundreds of similar sensors that are spread out as “large-N” sensing. Such sensor distributions have led to important advances in seismology and infrasound science, where they have improved our understanding of seismic ground motion and helped shed light on volcanic eruption dynamics [e.g., Rosenblatt et al., 2022; Anderson et al., 2023].
The benefits of large-N networks and arrays include robust spatial sampling and signal extraction from noise. They are also advantageous for detecting small signals, sensing natural hazards in remote environments, and offering critical redundancies for sensors at risk from lava or debris flows, wildfire, weather, or even malicious mammals.
Since 2013, our research group in the Department of Geosciences at Boise State University (BSU) has worked to study infrasound from geophysical phenomena by capitalizing on the benefits of low-cost, large-N sensing technology [e.g., Slad and Merchant, 2021]. More than a decade on, this effort has yielded scientific successes from a variety of environments, and it is continuing to evolve.
Large-N Sensing for Infrasound
Many violent natural processes, including landslides, volcanic eruptions, earthquakes, avalanches, and meteors, produce infrasound.
Many violent natural processes, including landslides, volcanic eruptions, earthquakes, avalanches, and meteors, produce infrasound, defined as low-frequency sound below the threshold of human hearing (less than 20 Hertz). Such events may create audible sound as well, but the subaudible band is often much more energetic in terms of sound intensity, and it has long wavelengths that can propagate long distances with little attenuation. These characteristics make infrasound especially valuable for remote sensing of natural phenomena.
Our group at BSU grew more interested in developing our own inexpensive infrasound sensing solutions after costing out technology for commercial data logging systems, the compact electronic devices that record and store sensor data. These systems can be far more expensive than infrasound transducers—the sensors that actually detect sound—themselves.
The cost element became particularly relevant after we lost instrumentation deployed at the summit of Chile’s Villarrica volcano when it erupted a 2-kilometer-tall lava fountain on 3 March 2015 [Johnson et al., 2018]. In an instant, our hardware, including seismic and infrasonic sensors and their commercial multichannel data loggers, was entombed beneath falling lava. This financial loss incentivized our work to develop low-cost loggers that would match the technical specifications and fidelity of commercial systems.
The result was the customized Gem infrasound logger, which we created using the widely available and very economical Arduino open-source electronic prototyping platform and its low–power consumption microcontroller. The Gem is an all-in-one infrasound sensor and data logger with a high dynamic range (millipascals to 100 pascals), a 100-hertz sample rate appropriate for infrasound, and a built-in GPS for precise timing and synchronization [Anderson et al., 2018].
Although we initially conceived of the Gem as an alternative to commercial loggers to be deployed as single stations or in small arrays, we quickly realized its potential for use in high-density distributed sensing arrays that enabled new detection capabilities. In particular, its small package size (it has about the dimensions and weight of a paperback novel) and its ease of deployment—simply insert alkaline batteries, place it on the ground, and turn it on—have opened opportunities for rapid, large-N deployments in difficult-to-access environments.
Early Successes for the Gem
Volcán Villarrica, near Pucon, Chile, is seen in 2025 (left). The volcano regularly releases gas from a small lava lake recessed deep within the summit crater (right). Credit: Jeffrey B. Johnson
The Gem’s inaugural field mission came in January 2020 during a return to Villarrica, where activity had returned to normal following its 2015 paroxysmal eruption [Rosenblatt et al., 2022]. Typical activity in the volcano’s normal state includes open-vent degassing from a small lava lake recessed deep within the summit crater, which produces its famously powerful volcano infrasound [e.g., Johnson et al., 2012].
To capture Villarrica’s infrasound in detail, a four-person team from BSU climbed the 3,000-meter-tall glaciated volcano and quickly installed 16 sensors around the crater rim, as well as another 16 sensors along an 8-kilometer linear transect from the summit down the northern slope (Figure 1). This unique sensor distribution permitted us to capture the infrasound wavefield and how it interacts with topography in unprecedented detail.
Fig. 1. (a) Oblique and (b) plan views of Villarica’s summit region were created from structure-from-motion surveys in 2020. Red triangles and circles indicate locations of Gem sensing packages. (c) Also in 2020, Jake Anderson adjusts a cable suspended across the volcano’s crater that held a Gem sensor (circled). (d) In 2025, Jerry Mock unloads Gem systems at Villarica’s summit during another data collection campaign there. Click image for larger version. Credit: Jeffrey B. Johnson
Deploying such an array configuration using much heavier, larger, and power-intensive conventional instruments would have taken far more time and resources, as well as a bigger group. With the Gems, however, the installation was feasible for our small team, each member of which could easily carry eight instruments and the batteries needed to power them.
To monitor volcanoes with infrasound, it is necessary to understand the influence of atmospheric effects.
Once in place, these sensors collected continuous data during the 2-week study that were used to quantify the diffraction of sound coming out of the volcanic crater [Rosenblatt et al., 2022] and to measure the sound’s attenuation as it propagated away. Such studies are important for investigating time-varying atmospheric parameters such as changing temperatures and winds, which can affect infrasound transmission, diminishing its amplitude or even—in extreme cases—completely silencing it in an acoustic shadow zone [Johnson et al., 2012]. To monitor volcanoes with infrasound, it is necessary to understand the influence of atmospheric effects.
Months later, another opportunity arose to demonstrate the Gems’ capability for large-N infrasound sensing. During the early days of the COVID-19 pandemic, on 31 March 2020, a magnitude 6.5 earthquake occurred near Stanley, Idaho. The earthquake, the largest in the state since 1983, kicked off an energetic aftershock sequence, with more than 700 magnitude 3 or greater earthquakes occurring in 6 months. Most of these events produced significant local infrasound radiation, or “airquakes,” caused by ground-atmosphere coupling [e.g., Johnson et al., 2020].
Pandemic-related precautions inhibited a large team from venturing as a group into the field. However, a lone BSU researcher (coauthor Jacob Anderson), trudging through forest terrain and deep snow on skis, was able to deploy and activate 22 Gems in less than 4 hours in early April, thanks in part to the sensors’ compact size and ease of deployment.
This array captured hundreds of local infrasonic aftershocks within about 25 kilometers of their epicenters. It also recorded a far larger event 700 kilometers away, the 15 May magnitude 6.5 Monte Cristo earthquake in Nevada. The array detected the epicentral infrasound from the distant earthquake source, as well as infrasound from numerous secondary sources, including mountain ranges throughout the western United States that reradiated the ground motion as infrasound (Figure 2) [Anderson et al., 2023].
Fig. 2. This map shows source region(s) of infrasound associated with the May 2020 Monte Cristo earthquake in Nevada that was detected by an array of Gem infrasound sensors deployed at the PARK site near Stanley, Idaho. Click image for larger version. Credit: Adapted from Anderson et al. [2023], CC BY 4.0
Detecting all these distinct signals was possible because of the enhanced array processing capabilities provided by the large number of sensors. Anderson et al. [2023] showed that when the data were processed from 3-sensor subsets of the 20+-sensor array—instead of from the whole array—it was possible to detect only the most intense earthquake infrasound arrivals. In other words, the larger array had much greater fidelity and sensing capabilities than smaller distributions of sensors.
During its 2-month deployment, the Stanley array also detected sounds from other distant nonearthquake sources, including waterfalls 195 kilometers away and thunder more than 900 kilometers away [Scamfer and Anderson, 2023]. Such enhanced detections, facilitated by large-N sensing, demonstrate an improved capacity to monitor a range of Earth phenomena continuously over a wide range of distances.
Putting Sensors in Harm’s Way
Since those proof-of-concept deployments, Gems have been used to monitor snow avalanches, lahars, river flow discharge, stratospheric sounds (while mounted aboard a solar balloon), and numerous volcanoes during field experiments [e.g., Tatum et al., 2023; Bosa et al., 2024; Rosenblatt et al., 2022; Brissaud et al., 2021]. Given their ease of use, small size, and low replacement cost, they’ve also been tested in hazardous environments where the risk to more expensive hardware could be considered unreasonable.
The motivation to put sensors in harm’s way is to gain insight into geophysical phenomena by recording subtle signals close to the source that may not be detectable from farther away.
The motivation to put sensors in harm’s way is to gain insight into geophysical phenomena by recording subtle signals close to the source that may not be detectable from farther away. For example, at Villarrica, Rosenblatt et al. [2022] suspended a Gem on a cable 100 meters above a lava lake to collect infrasound data from a unique, bird’s-eye perspective over the crater (Figure 1c). (Stringing the cable across the crater proved far more challenging than deploying the sensor itself, which slid down the cable until finding its resting place at the bottom of the cable’s arc.)
In another case, we landed a pair of Gems on the ground near a frequently exploding crater at Fuego volcano in Guatemala using a drone (see video below). We later retrieved one of the sensors from high on the volcano’s flanks. Another was lost because high winds initially posed too great a risk to fly the drone back for it. Then the following day after the wind subsided, we could not locate the stranded Gem, which was probably a casualty of a nighttime explosion.
Drone footage and infrasound recordings were collected during an explosion of Fuego volcano on 4 February 2024. Pa = pascals. Credit: video: Jerry C. Mock; animation and infrasound: Jeffrey B. Johnson
Our group at BSU also has nascent interest in using Gems to study fire in natural environments. Wildfires produce infrasound from a spatially extensive source region corresponding to actively burning areas. Because of the source complexity and the fact that fire infrasound is low amplitude and tremor-like [Johnson et al., 2025], enhancing signal-to-noise ratios in recorded infrasound is critical. This enhancement is enabled by using large-N monitoring networks, making infrasound wildfire surveillance a promising area of investigation.
Low-cost, rapid infrasound deployments could one day be used as an effective operational tool.
Toward this objective, our group installed 76 sensors ahead of a prescribed burn in Reynolds Creek, Idaho, in October 2023 to begin developing infrasound as a tool for monitoring and mapping wildfire. We have also deployed Gems for infrasound studies of naturally occurring wildfires, such as the Emigrant wildfire in Oregon in August and September 2025 (Figure 3). During that active wildfire response, a team safely and quickly installed tens of sensors within a matter of hours in an area facing dynamic hazards from the rapidly expanding fire, which eventually covered 33,000 acres (about 13,354 hectares). Luckily, no instruments were lost, and the data have shown the potential to track a wildfire as it advances.
Preliminary results suggest that low-cost, rapid infrasound deployments could one day be used as an effective operational tool. For example, in firefighting responses, infrasound might complement intermittent aerial observations, from aircraft or drones, because it provides a continuous record of fire activity. Infrasound surveillance might also be able to “hear” combustion sources within a burn area that is obscured to optical sensing because of clouds or nightfall.
Fig. 3. (a) The spread and severity of the 2025 Emigrant Fire in Oregon, as calculated from prefire (21 August) and postfire (18 October) Sentinel-2 satellite images, are shown. Inset maps show the distribution of 37 Gem sensors rapidly deployed in three arrays. (b) Smoke from the fire rises from the landscape on 31 August during deployment of the sensors. (c) Following the fire, one sensor that had been melted by the fire was recovered with its data card still intact (red circle). dNBR = differenced normalized burn ratio. Click image for larger version. Credit: (a) and (b): Madeline A. Hunt; (c): Jacob F. Anderson
The Evolution of Low-Cost Sensors
Five years ago, the single-sensor Gem was a cutting-edge infrasound logging solution. While it remains a powerful and economical tool for large-N arrays and for sensing in hostile environments, it is evolving.
Boise State University researchers (left to right) Madeline Hunt, Owen Walsh, Jerry Mock, and Jacob Anderson prepare to deploy Gem sensors in Idaho’s Sawtooth Mountains in January 2024. Credit: Jeffrey B. Johnson
We have now developed the Gem into an even more versatile version called the Aspen, which can log four independent sensors at a sample rate of 200 hertz, double that of the Gem. The Aspen retains the small size, low weight, low power consumption, and low cost of the Gem, but with the capability to record higher-resolution 24-bit, time-synchronized data from a triaxial seismic sensor and an infrasound transducer.
Recording synchronous seismoinfrasonic data on the same logging platform offers the advantage of sensing both ground shaking and infrasonic oscillations. The ability to measure waves propagating in the ground and in the air simultaneously could facilitate work in the growing field of environmental seismology, which focuses on geophysical sources at Earth’s surface like debris flows and volcanoes.
Although we have focused on seismoacoustic geophysical measurements in our work, the concept of gathering data with low-cost instrumentation in harm’s way or from coordinated arrays of numerous sensors holds promise across Earth and environmental sciences. Such approaches could be used, for example, with tiltmeters (which measure slope changes), gravity meters, or near-infrared thermometers (e.g., optical pyrometers), all of which would offer additional data streams complementing seismoacoustic observations in geophysical studies of volcanoes.
With the diversity of emerging uses, it’s clear that large-N sensing—infeasible or cost prohibitive in many cases until recently—could transform how we measure many facets of Earth, helping to reveal the inner workings of volatile volcanoes, twisting tornadoes, and more.
Acknowledgments
More information about low-cost infrasound sensing solutions can be found at https://sites.google.com/boisestate.edu/infravolc/home. Development of the Gem infrasound logging platform was supported by a grant from the National Science Foundation (EAR-2122188).
References
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Bosa, A. R., et al. (2024), Dynamics of rain-triggered lahars and destructive power inferred from seismo-acoustic arrays and time-lapse camera correlation at Volcán de Fuego, Guatemala, Nat. Hazards, 121, 3,431–3,472, https://doi.org/10.1007/s11069-024-06926-1.
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Scamfer, L. T., and J. F. Anderson (2023), Exploring background noise with a large‐N infrasound array: Waterfalls, thunderstorms, and earthquakes, Geophys. Res. Lett., 50, e2023GL104635, https://doi.org/10.1029/2023GL104635.
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Tatum, T., J. F. Anderson, and T. J. Ronan (2023), Whitewater sound dependence on discharge and wave configuration at an adjustable wave feature, Water Resour. Res., 59, e2023WR034554, https://doi.org/10.1029/2023WR034554.
Author Information
Jeffrey B. Johnson (jeffreybjohnson@boisestate.edu), Jacob F. Anderson, Madeline A. Hunt, Owen A. Walsh, and Jerry C. Mock, Department of Geosciences, Boise State University, Idaho
Citation: Johnson, J. B., J. F. Anderson, M. A. Hunt, O. A. Walsh, and J. C. Mock (2026), Sensing the sounds from Earth’s hazardous environments, Eos, 107, https://doi.org/10.1029/2026EO260142. Published on 8 May 2026.
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