How to Find Lunar Ice? Moonquakes to the Rescue!

The surface of the Moon is a bleak and forbidding place, swept by radiation, scorched by the Sun on one side and frozen in perpetual shadow on the other. Yet beneath this austere landscape may lie one of the most valuable resources in the solar system: water ice. Identifying, locating, and ultimately extracting that ice is one of the central challenges of 21st-century lunar exploration. Now, a team of geologists has proposed an elegant solution — using the Moon's own seismic tremors, known as moonquakes, as subsurface locator beacons to pinpoint hidden ice deposits with unprecedented precision.

Researchers at the University of Maryland, Lawrence Berkeley National Laboratory, and the University of Hawai'i recently published a landmark study examining the role that seismic waves play in locating ice deposits on and within the Moon. Their findings represent a significant step forward in our ability to survey the lunar interior for frozen water, and could prove essential to the long-term success of crewed missions in the coming decades.

"It's crucial to identify any materials on the moon that an astronaut can make use of while they're up there. Since they will be limited by the few resources they brought from Earth, anything they find on the moon will help them basically live off the land, especially for longer-term missions or outposts." — Nicholas Schmerr, University of Maryland

Why Lunar Ice Matters

Before diving into the science of detection, it is worth understanding why scientists and space agencies are so keenly focused on finding lunar water ice. The answer lies not just in scientific curiosity, but in the hard economics of space exploration. Transporting a single kilogram of material from Earth's surface to the Moon costs tens of thousands of dollars, making the logistics of supplying a permanent lunar base with water almost prohibitively expensive if it must be shipped from home.

Lunar ice, by contrast, could serve as an in-situ resource of extraordinary value. When processed, water ice can be:

Purified and used directly as drinking water for astronauts
Electrolyzed to produce breathable oxygen for habitats and spacesuits
Split into liquid hydrogen and liquid oxygen, the classical components of rocket propellant, enabling missions to travel farther into the solar system
Used for radiation shielding, as water is an effective barrier against harmful cosmic rays and solar particle events
Studied as a scientific archive, preserving a record of cometary and asteroid impacts stretching back billions of years

According to Nicholas Schmerr of the University of Maryland, who co-authored the study, the upcoming NASA Artemis missions and other international lunar programs will depend heavily on being able to locate and exploit these deposits. The ability to "live off the land" on the Moon — a concept known in spaceflight as In-Situ Resource Utilization (ISRU) — is considered essential to making sustained lunar presence economically and logistically feasible.

How Did the Moon Get Water?

The origins of the Moon's water caches remain something of a scientific mystery, though a compelling body of evidence points in several intriguing directions. The most likely locations for substantial accumulations are the permanently shadowed regions (PSRs) near the lunar poles — deep craters where sunlight never reaches and temperatures can plunge below –250°C (–418°F), cold enough to preserve ice for billions of years.

Several mechanisms have been proposed to explain how water arrived and accumulated on the Moon:

Cometary and asteroidal delivery: Impacts from water-rich bodies in the early solar system may have deposited significant quantities of ice, particularly during the period known as the Late Heavy Bombardment, approximately 3.9 billion years ago.
Volcanic outgassing: Ancient lunar volcanism may have transported water molecules from the deep interior to the surface, where they could migrate toward the cold poles and freeze.
Solar wind interactions: Hydrogen ions carried by the solar wind can react with oxygen-bearing minerals in lunar regolith to form hydroxyl (OH) and water molecules (H₂O) — a continuous process that may still be occurring today.
Meteoritic bombardment: Micrometeorite impacts can trigger chemical reactions in surface rocks, releasing trapped water molecules into the tenuous lunar exosphere, where they may drift toward and settle in cold polar traps.
Primordial water: Some analyses suggest that water may date back to the very formation of the Moon, preserved from the material of the early proto-Earth that was ejected during the giant impact with a Mars-sized body called Theia roughly 4.5 billion years ago.

The evidence for lunar water is now substantial and multifaceted, drawn from studies of rocks returned during the Apollo era, spectroscopic data from NASA's SOFIA airborne observatory, mineralogical mapping by India's Chandrayaan-1 spacecraft, and sample analysis from China's Chang'e 5 probe. It is now widely accepted that lunar water is not a single-event phenomenon, but rather the cumulative result of multiple delivery and generation mechanisms acting over billions of years.

Recent spectroscopic analyses suggest there may be between 100 and 400 milligrams of water per gram (mg/g) of lunar soil in certain regions — a concentration that, while modest by Earth standards, could be sufficient for industrial-scale extraction if deposits are large and accessible enough. Scientists also suspect that the lunar water is likely a complex, briny mixture of indigenous lunar materials combined with chondritic materials delivered by impacts — similar in some ways to the salt-rich subsurface brines found in extreme environments here on Earth.

The Challenge of Finding Hidden Ice

Despite the growing evidence for its existence, actually locating lunar ice deposits is surprisingly difficult. Ice in permanently shadowed craters does not conveniently announce itself in standard optical images. Even infrared spectroscopy — which has been used to detect the spectral signature of water molecules — struggles to peer beneath the surface to determine where bulk ice deposits might reside at depth. What is needed is a technique capable of probing the lunar subsurface directly, in a manner analogous to how medical imaging reveals structures inside the human body.

This is where seismic wave analysis enters as a game-changing tool. Geophysicists have long used earthquake waves to probe Earth's deep interior, discovering everything from the structure of the mantle to the liquid outer core. The same physics, applied to the Moon, offers a powerful window into the subsurface — including the potential to distinguish ice-bearing layers from dry regolith with high confidence.

Seismic Waves as Subsurface Probes

When a moonquake occurs — whether triggered by tidal stresses from Earth's gravity, thermal expansion and contraction of the crust, or residual geological activity — it radiates mechanical energy outward in all directions as seismic waves. These waves travel through whatever materials they encounter, and their behavior — speed, direction, amplitude, and the way they reflect or refract — is exquisitely sensitive to the physical properties of those materials.

The key properties that determine seismic wave behavior are density and elastic modulus (a measure of a material's resistance to deformation). Ice, being a rigid crystalline solid with a relatively high elastic modulus, allows seismic waves to travel significantly faster than through loose, unconsolidated regolith or dry sand. Quantitatively, seismic waves can travel two to three times faster through ice-rich material than through ice-free lunar soil — a dramatic difference that should be readily detectable with sensitive instruments.

Moreover, when seismic waves encounter the boundary between different materials — say, a layer of ice beneath dry regolith — some of their energy is reflected back toward the surface, a phenomenon known as seismic reflection. By analyzing these reflected signals alongside the wave velocities, scientists can not only confirm the presence of ice but also estimate its depth, thickness, and even its concentration within the surrounding material.

"We can use seismic waves to not just see whether ice is present but also roughly how much of it there is." — Nicholas Schmerr, University of Maryland

This dual capability — detection and quantification — makes seismic wave analysis a uniquely powerful tool for lunar ice prospecting. It is, in effect, a form of subsurface ultrasound for the Moon, capable of revealing hidden structures that no camera or surface spectrometer could ever see.

A Three-Pronged Experimental Approach

The research team, led by Harrison Lisabeth of Lawrence Berkeley National Laboratory, devised an innovative three-part methodology to test whether seismic wave analysis could realistically detect lunar ice. Each approach addressed a different aspect of the problem, and together they built a compelling, interlocking case.

1. X-Ray Tomography of Simulated Lunar Regolith

The first approach was elegantly hands-on. The team sourced volcanic basalt rock from Arizona, a material whose mineralogical composition closely mirrors that of lunar regolith. When crushed to a fine powder, this rock produces a near-perfect physical analog for the dust covering the Moon's surface. The team froze water into this simulated regolith and then subjected it to X-ray tomography — essentially a high-resolution 3D scan — to visualize exactly how ice settles and bonds within the dust structure at a microscopic level.

The results were striking. Rather than forming discrete isolated chunks, the ice acted like a cement, filling the tiny pore spaces between individual dust grains and binding them together into a more rigid matrix. This cementing effect is precisely what would cause seismic waves to travel faster through ice-bearing regolith — the increased rigidity of the composite material directly elevates the material's elastic modulus and therefore the seismic wave velocity. This micro-structural understanding is crucial because it confirms the physical mechanism underlying the detection technique.

2. Temperature Modeling of Polar Regions

The second approach employed thermal modeling of the lunar polar environment. The permanently shadowed regions near the lunar poles are among the coldest places in the entire solar system, but temperature is not perfectly uniform even within them. Subtle variations in topography — the angle of crater walls, the depth of depressions, proximity to illuminated terrain — create a complex thermal landscape that determines exactly where ice can stably persist over geological timescales.

By building detailed temperature models of these polar regions, the team was able to identify where ancient ice deposits are most likely to have survived undisturbed, insulated from the Sun's warmth by billions of years of perpetual shadow. These models provide critical input for planning where seismic surveys should be focused to maximize the probability of detecting significant deposits.

3. Computer Simulations of Moonquake Interactions

The third approach, led by Schmerr himself, involved running sophisticated computer simulations of minor moonquakes and modeling how the resulting seismic waves would interact with underground ice deposits of varying concentrations and geometries. These simulations allowed the team to predict the specific seismic signatures — velocity anomalies, reflection patterns, wave attenuation — that would indicate the presence of ice at depth.

Crucially, all three methods produced clear, unambiguous signals of ice in the data. The convergence of results across such different experimental approaches provides strong validation that seismic wave analysis is a genuinely viable and reliable technique for locating lunar ice.

Ice as a Window into Solar System History

Beyond its practical value as a resource, lunar ice holds immense scientific significance as a time capsule of solar system history. The permanently shadowed craters near the poles have remained undisturbed for billions of years, potentially preserving pristine samples of cometary material, asteroid debris, and other ancient volatiles that have been erased from Earth's ever-changing geological record.

Studying the composition and isotopic signatures of this ancient ice could shed light on some of the most fundamental questions in planetary science: How was water delivered to the inner solar system? What was the role of comets versus asteroids in seeding Earth's oceans? How did the early solar system evolve chemically during its first few hundred million years?

"The moon witnessed some of the most critical parts of the early solar system, including how water was delivered. Studying the ice deposited there could reveal how water spread and ultimately how Earth's oceans formed." — Nicholas Schmerr, University of Maryland

In this sense, the hunt for lunar ice is not merely an engineering exercise in resource prospecting — it is also a profound scientific journey into the origins of habitability in the inner solar system, with implications that extend far beyond the Moon itself.

Recommendations and the Road Ahead

Based on their three-pronged experimental results, the research team put forward several concrete recommendations for advancing lunar ice detection capabilities:

Expand regolith analog studies: Future laboratory work should test a wider array of simulated lunar soil compositions to refine our understanding of how ice microstructures form and behave under different conditions.
Improve topographic models: Computer simulations should incorporate more accurate, high-resolution measurements of lunar surface topography — particularly in polar regions — to better predict where ice is likely to accumulate and persist.
Develop targeted seismic networks: More extensive seismic modeling and physical testing should be conducted to refine the ability to pinpoint ice locations and depths with precision sufficient for resource planning.
Deploy dedicated instrumentation on upcoming missions: Future lunar landers and surface assets should carry sensitive seismometers specifically designed and positioned to survey ice-bearing regions.

The timing of these recommendations is fortuitous, as several upcoming missions are poised to provide exactly the kind of data the team is calling for. China's Chang'e-7 mission, targeting a landing site near the scientifically rich Shackleton Crater at the lunar south pole, is planned to carry a seismometer capable of searching for subsurface ice signatures. The European Space Agency is also developing instruments for lunar surface geophysics as part of broader international lunar exploration initiatives.

Meanwhile, the 2028 Artemis crewed landing mission is expected to deploy a Lunar Environmental Monitoring Station (LEMS), a compact seismic station that could perform ongoing subsurface surveys of the landing area and its surroundings. The data returned by these instruments will represent the most detailed seismic survey of the Moon since the Apollo-era Passive Seismic Experiment, which operated from 1969 to 1977 and first revealed the Moon's complex seismic character to scientists on Earth. Visit

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Detecting Hidden Water on the Moon Using Seismic Activity