Plowing, or tilling, is an age-old agricultural practice that readies the soil for planting by turning over the top layer to expose fresh earth. The method — intended to improve water and nutrient circulation — remains popular today, but concerns about soil degradation have prompted some to return to regenerative methods that disturb the soil less.

In a new study, a team led by 91̽�� researchers examined the impact of tilling on soil moisture and water retention using methods originally designed for monitoring earthquakes. Researchers placed fiber optic cables alongside fields at an experimental farm in the United Kingdom and recorded ground motion from plots receiving different amounts of tillage and compaction from tractor tires pulling farm equipment.

The study, , shows that tilling and compaction disrupt intricate capillary networks within the soil that give it a natural sponge-like quality.

“This study offers a clear explanation for why the process of tillage, one of humanity’s oldest agricultural activities, changes the structure of soil in ways that affect how it soaks up water,” said co-author , a 91̽��professor of Earth and space sciences.

The link between tilling and soil degradation has been established for quite some time, but the rationale is less robust.

“It’s counterintuitive,” Montgomery said.

Tilling is supposed to create holes for water to reach the roots of plants, but it breaks these small channels in the soil instead, causing rain to pool on the surface and form a muddy crust. Over time, this can increase erosion and flood risk. The researchers observed this phenomenon in detail using seismological methods.

For the past decade or so, physical scientists have been exploring ways to harness the fiber optic cable network to make remote observations. They use a technique called distributed acoustic sensing, or DAS, that records ground motion based on cable strain. Because the technology is so sensitive, it can also capture the speed at which sound waves pass through a substance, which is called seismic velocity.

When soil gets wet, seismic velocity changes. Sound moves slower through mud than dry dirt.

“We wanted to find out whether seismic tools could be used to understand how soil — under different treatment regimens — would respond to environmental variability,” said senior author , a 91̽��associate professor of Earth and space sciences.

An experimental farm near Newport in the United Kingdom, affiliated with Harper Adams University, turned out to be an ideal testing ground for their experiment.

The farm is split into rows that have received consistent cultivation for more than two decades.

There are no-till rows, rows tilled 10 centimeters deep and rows tilled 25 centimeters. Compaction is a byproduct of tilling caused by tractors. Different levels of compaction were tested by modulating tractor tire pressure.

“We took advantage of a natural experiment that had already been done, but just not yet measured,” Montgomery said.

The researchers lined their experimental plots with a fiber optic cable. They collected continuous ground motion data for 40 hours and combined it with weather data over the same period, which featured light to moderate rainfall and mild temperatures.

“We observed the natural vibration of the ground and found that it is really sensitive to environmental factors, including precipitation,” said , lead author and former 91̽��postdoctoral researcher of Earth and space sciences, now at the Chinese Academy of Sciences.

They determined how each cultivation strategy impacted the soil’s response to rainfall by comparing trends in seismic velocity across study sites. Shi developed various models to process the data and help the researchers understand seismic velocity in terms of soil moisture.

The method is straightforward, inexpensive and offers far better spatial and temporal resolution than previous monitoring tools.

The researchers believe it could help farmers understand how to manage their land, provide real time flooding alerts, improve earth systems models by refining estimates of atmospheric water content and better inform seismic hazard maps with data on liquefaction risk.

Additional co-authors include , a 91̽��professor of atmospheric and climate science, , a 91̽��research assistant professor of civil and environmental engineering, from the University of California Santa Cruz, formerly at Purdue University, , , and from Harper Adams University, from the University of Exeter 

This study was funded by The Pan Family Fund, the Murdock Charitable Trust, the 91̽��College of the Environment Seed Fund, the David and Lucile Packard Foundation, and a National Environmental Research Council cross-disciplinary research capability grant.��

For more information, contact Denolle at mdenolle@uw.edu.��

The Cascadia Subduction Zone is unusually quiet for a megathrust fault. Spanning more than 600 miles from Canada to California, the fault marks the convergence of the Juan de Fuca and North American plates. While other subduction zones produce sporadic rumblings as the plates scrape past each other, Cascadia , fueling assumptions that the plates are locked together by friction.

The subduction zone — miles offshore and deep underwater — is difficult to observe. Most data collection is based onshore, which limits the breadth and quality of results. The lack of earthquakes further complicates efforts to understand its behavior and structure.

In a new study, the first to monitor strain offshore for an extended period of time, 91̽�� researchers report that the plates may not be fully locked. Based on 13 years of ground motion data from sensors in different regions, the study shows the northern portion of the fault is locked and quiet, but the central region appears to be more active. There, researchers observed signs of a shallow, slow-motion earthquake and detected pulses of fluid flowing through subterranean channels, which may relieve pressure from the fault.

The findings, , may alter expectations of how this area will respond to a large earthquake. Similar features in other places have stopped a rupture that might have otherwise continued along the entire fault line.

“It’s preliminary, but we think that variable fluid pathways in Cascadia will change the behavior of large earthquakes on the fault,” said co-author , a 91̽��associate professor of Earth and space science.

The Juan de Fuca plate is advancing toward the North American plate at a rate of . But because the plates are stuck together, that motion generates pressure. Eventually, the building tension will exceed what the plates can tolerate. When they eventually slip free, an earthquake will spread along the boundary.

Megathrust earthquakes, which occur at boundaries where one plate slides beneath another, rock the Pacific Northwest every 500 or so years. one to 1700, and estimates suggest a 10 to 15% chance that the entire fault will rupture, producing an earthquake that could exceed magnitude 9, within the next fifty years. The results from this study do not alter those odds, but the dynamics captured might influence the severity of the eventual earthquake.

A recent survey of the seafloor found that into at least four geologically distinct segments. Each one may be insulated from a rupture in another region. In this study, the researchers took a closer look at two of the regions by analyzing data from three monitoring stations, one near Vancouver Island and two off the coast of Oregon.

“We wanted to understand strain changes in different regions offshore,” said lead author , a 91̽��doctoral student of oceanography. “We used the seismometers to measure how the seismic velocity varies underneath each station.”

Seismic velocity is a term used to describe the rate at which ambient noise travels through a material. Because the speed of sound depends on what it is moving through, tracking seismic velocity can give researchers a window into processes occurring beneath the ocean floor.

“When you compact something, you can expect the sound waves to move through it faster,” said Kidiwela.

The steady increase in seismic velocity observed at the northern site told the researchers the rock was compacting, which supports the theory that the two plates are locked in place.

The central region displayed a different pattern. For two months in 2016, seismic velocity decreased. The researchers attribute this drop to a slow-motion earthquake on the shallow edge of the oceanic plate that relieved some of the pressure at the fault.

Other drops in seismic velocity, recorded between 2017 and 2022, were linked to fluid dynamics. Subduction squeezes liquid out of rocks and pushes it toward the surface. The study found that other faults, running perpendicular to the subduction zone, may act as pathways for letting trapped fluid out.

“During a megathrust rupture, one of the ways that an earthquake propagates is through fluid pressure. If you have a way to release these fluids, it could help improve the stability of the fault, and potentially impact how the region behaves during a large earthquake,” Kidiwela said.

Pulling data from just three sites, the researchers observed complex dynamics that may have gone overlooked. Future work will greatly expand this effort. in 2023 to build an underwater observatory in the Cascadia Subduction Zone.

“Finding this link between fluids coming to the shallow subduction zone is pretty unique, as is the evidence that the fault is not completely locked,” said co-author , a 91̽��professor of oceanography and one of the scientists involved with the observatory. “It suggests that we need more instruments there, because there may be more going on than people have been able to figure out before.”

Additional co-authors include from the University of Utah.��

This study was funded by the Jerome M. Paros Endowed Chair in Sensor Networks at the 91̽�� and the National Science Foundation.��

For more information, contact Kidiwela at seismic@uw.edu.

The Pacific Northwest boasts an extensive network of more than 600 seismic monitoring stations that help researchers track tectonic and volcanic phenomena, including earthquakes. This data provides key insights into regional faults and feeds into early warning systems, which can give a community precious moments to prepare before a natural disaster strikes. A significant threat to this region, however, sits miles offshore, where the Juan de Fuca plate is subducting beneath the North American plate, forming the Cascadia Subduction Zone.

Monitoring activity at ocean floor faults is challenging, and the existing methods don’t often yield enough data for detailed analyses. To overcome this hurdle, researchers are experimenting with a technique called Distributed Acoustic Sensing, or DAS, that involves measuring ocean bottom vibrations with fiber optic cables, which line the ocean floor for global telecommunications. Recent advances enable researchers to collect data from live cables and use artificial intelligence to capture distant earthquakes that would otherwise escape notice.

In a recent study, 91̽�� researchers tapped into the Ocean Observatory Initiative’s Regional Cabled Array, which spans the offshore plate boundary and transmits data via fiber optic cable. Unlike previous experiments that relied on offline or “dark fibers” for data collection, this new study demonstrates that DAS technology can operate without interfering with the OOI network.

The researchers February 28 in Seismological Research Letters.

“What we created is the starting point of any earthquake analysis,” said co-author , a 91̽��associate professor in the Earth and space sciences department. “Once our AI algorithm enhances the data, we can actually use the wiggles to do science.”

The fiber optic cable network caught researchers’ attention in the last decade, when they realized its potential for recording solid Earth data. The cables transmit bits of information across great distances in the form of photons, or particles of light. A sensor — called an interrogator — sends a pulse of light down the cable, but imperfections in the core sometimes cause light to deflect back toward the signal’s origin.

Disturbances near the cable can knock the deflected particles off course, and when they arrive back at the origin, researchers plot their path to locate the disturbance.

“When the earthquake is small or faraway, the energy on the cable is relatively low compared to the ocean, and the signal gets buried in background noise,” said co-author, a former 91̽��postdoctoral researcher in the Earth and space sciences department who is now a seismologist at Rice University.

, 91̽��researchers developed an algorithm that isolates the signal and amplifies it over the background noise by as much as 2.5 times. All they have to do is let the algorithm explore the data and it will learn how to recognize the signal — in this case, an earthquake. The researchers used data from 285 earthquakes that occurred in Alaska’s Cook Inlet in 2023 as the training dataset.

“A well-trained model will identify earthquakes that the human eye cannot see,” Shi said. “This marks the first step toward a general-purpose foundational model for earthquakes”

To confirm that it would also filter data collected elsewhere, the researchers validated their model at the test site in Oregon, using a live cable. Previous experiments, including the test-run in Alaska, have sourced data from inactive cables, or dark fibers.

In Oregon, the researchers demonstrated that they could collect high-quality data while the cables were transmitting data. They plugged into the Regional Cabled Array, which contains fiber optic cables, and tuned the algorithm to the frequency of seismic waves coming from small- to medium-sized earthquakes far away. The researchers then traced the signal back to specific regions of the subduction zone and pinpointed the precise location of an earthquake.

“It’s the closest we can get to where the action is,” Denolle said. “So for addressing scientific questions, for monitoring, and for early tsunami and earthquake warnings, it’s our best shot.”

The system is also portable, requiring just a modest amount of computing power to operate.

The recent experiment in Oregon lasted just 3 days and produced large volumes of high-quality data, arguably more than the team knows what to do with, Denolle added. Their challenge now is figuring out how to manage the data. Both datasets were published free to access, and the one from Alaska is the largest single-site data of its kind. The team is now in the process of negotiating permanent placements for their monitoring system and exploring collaborations.

“This is the future,” Denolle said. “We’re going to understand plate tectonics by studying small earthquakes and this system gives us unprecedented access to that data.”

Additional co-authors on this paper are , a postdoctoral researcher in the Earth and space sciences department; , an assistant professor in the Earth and space sciences department; , a professor in the oceanography department; a professor in the oceanography department and director of the Ocean Observatory Initiatives Regional Cabled Array and , a research coordinator in Earth and space sciences.

This research was funded by the National Science Foundation, U.S. Geological Survey, David and Lucile Packard Foundation, 91̽��Geohazard Initiative and Jerome M. Paros Endowed Chair in Sensor Networks.

For more information, contact Shi at qibins@uw.edu and Denolle at mdenolle@uw.edu.

There’s enough water frozen in Greenland and Antarctic glaciers that if they melted, global seas would rise by many feet. What will happen to these glaciers over the coming decades is the biggest unknown in the future of rising seas, partly because glacier fracture physics is not yet fully understood.

A critical question is how warmer oceans might cause glaciers to break apart more quickly. 91̽�� researchers have demonstrated the fastest-known large-scale breakage along an Antarctic ice shelf. The , recently published in AGU Advances, shows that a 6.5-mile (10.5 kilometer) crack formed in 2012 on Pine Island Glacier — a retreating ice shelf that holds back the larger West Antarctic ice sheet — in about 5 and a half minutes. That means the rift opened at about 115 feet (35 meters) per second, or about 80 miles per hour.

“This is to our knowledge the fastest rift-opening event that’s ever been observed,” said lead author , who did the work as part of her doctoral research at the 91̽��and Harvard University and is now a postdoctoral researcher at Stanford University. “This shows that under certain circumstances, an ice shelf can shatter. It tells us we need to look out for this type of behavior in the future, and it informs how we might go about describing these fractures in large-scale ice sheet models.”

A rift is a crack that passes all the way through the roughly 1,000 feet (300 meters) of floating ice for a typical Antarctic ice shelf. These cracks are the precursor to ice shelf calving, in which large chunks of ice break off a glacier and fall into the sea. Such events happen often at Pine Island Glacier — the iceberg observed in the study has long since separated from the continent.

“Ice shelves exert a really important stabilizing influence on the rest of the Antarctic ice sheet. If an ice shelf breaks up, the glacier ice behind really speeds up,” Olinger said. “This rifting process is essentially how Antarctic ice shelves calve large icebergs.”

In other parts of Antarctica, rifts often develop over months or years. But it can happen more quickly in a fast-evolving landscape like Pine Island Glacier, where researchers believe the West Antarctic Ice Sheet has already passed a tipping point on its collapse into the ocean.

Satellite images provide ongoing observations. But orbiting satellites pass by each point on Earth only every three days. What happens during those three days is harder to pin down, especially in the dangerous landscape of a fragile Antarctic ice shelf.

For the new study, the researchers combined tools to understand the rift’s formation. They used seismic data recorded by instruments placed on the ice shelf by other researchers in 2012 with radar observations from satellites.

Glacier ice acts like a solid on short timescales, but it’s more like a viscous liquid on long timescales.

“Is rift formation more like glass breaking or like Silly Putty being pulled apart? That was the question,” Olinger said. “Our calculations for this event show that it’s a lot more like glass breaking.”

If the ice were a simple brittle material, it should have shattered even faster, Olinger said. Further investigation pointed to the role of seawater. Seawater in the rifts holds the space open against the inward forces of the glacier. And since seawater has viscosity, surface tension and mass, it can’t just instantly fill the void. Instead, the pace at which seawater fills the opening crack helps slow the rift’s spread.

“Before we can improve the performance of large-scale ice sheet models and projections of future sea-level rise, we have to have a good, physics-based understanding of the many different processes that influence ice shelf stability,” Olinger said.

The research was funded by the National Science Foundation. Co-authors are and , both 91̽��faculty members in Earth and space sciences who began advising the work while at Harvard University.

For more information, contact Olinger at solinger@stanford.edu.

The Cascadia Subduction Zone is a massive geologic fault that last ruptured in January 1700. But while this fault has stayed quiet for centuries, it regularly generates small tremors that accompany gradual, nondisruptive movement along the fault.

The tiny tremor events and slow slippage are known collectively as “.” Seismic waves associated with these tremor events are recorded and tracked by the UW’s Pacific Northwest Seismic Network. Other groups track the associated slow motion of the plates using GPS measurements. These paired types of events occur regularly and seem to fluctuate with tidal cycles, but they originate deep underground and their cause has been mysterious.

A pair of papers published Jan. 29 provides new confirmation of speculations about a cause of these events. Taken together, the papers show that fluids deep underground create fractures in the rock, and that this creates rumblings that match what we observe at the surface.

, an assistant professor of Earth and space sciences at the UW, and , an affiliate associate professor at the 91̽��who is based with the U.S. Geological Survey, are co-authors on the about the experimental findings.

Denolle began advising lead author Congcong Yuan as a faculty member at Harvard before joining the 91̽��faculty in 2022. Denolle and Gomberg sat down with 91̽��News to answer some questions about the study, and what it means for the Cascadia region.

91̽��News: What are slow slip earthquakes? And how are slow slip events related to larger, more damaging earthquakes?

Joan Gomberg: When cracks form really quickly, that’s an earthquake. When the rock beneath the surface breaks and moves really fast, and that sends out these big loud vibrations that travel as waves and can knock down buildings. So you care about that a lot.

But sometimes the same thing happens really slowly. So slowly that it doesn’t send out big waves. And it makes these little, tiny little rumblings and shaking, but nothing gets knocked down.

Marine Denolle: The slow earthquakes in Cascadia are a bit more predictable and tractable than large earthquakes. Slow events are accompanied by the “pops” that we detect as tremor at the surface every 12 to 15 months, so they are semi-periodic. These tremor signals, or the “pops” are tracked by the Pacific Northwest Seismic Network — not the larger-scale, slow, absolute fault displacement.

JG: These pops, even though they don’t hurt anything, are really just telling you that something is happening. They’re telltale evidence that yes, something is moving, something is going on. In seismology we call it a passive marker. It’s just a little something chattering, saying: ‘Hi, I’m here, I’m moving!’

Can you describe this experiment that forms the basis of the new AGU Advances paper?

MD: At Harvard we had the apparatus to 3-D print materials, inject high pressure fluid in it, and have a high-speed camera to observe how hydrofracturing cracks the material. What we wanted to do is listen to the sound of the fracture and find the source of the acoustic emissions — sound waves — or vibrations, to map the geometrical expansion of the fracture. We can’t see through rocks, so we wanted to make this experiment with a transparent sample, where we have the ground-truth between acoustic emissions and visualization of the fracture growth.

Because we could see through the sample this slow-growing fracture that has all these pops, we realized that this looks like what we’d see in nature for slow-slip earthquakes, except that we had to invoke the use of fluids to drive the fracture.

Our results show a potential model for slow earthquakes. They are related to the faster earthquakes, in the sense that they relieve stress and they may load stress nearby for future earthquakes. Understanding the behavior at all scales and at all speeds is part of understanding earthquakes that eventually will matter for damaging ground motion.

Your research found that hydraulically driven fractures are causing the seismic signals we observe at the surface. Deep in the Earth, where is the fluid coming from?

JG: Most rocks are in solid form but they have H2O bound up inside of them. It’s not fluid, but it’s got hydrogen and oxygen, and under certain conditions deep in the Earth, when the temperatures and pressures get large enough, that actually does get released. It isn’t melting. It’s just with sufficient pressure and temperature the water is released from of the minerals.

Two papers are being published at the same time. Can you explain how they relate to one another, and to the seismology we observe in nature?

MD: The paper by our colleagues is about the mechanics of these fractures. And our paper in is about how can we provide an analogy, or a model, to the natural world. How can this mechanistic model provide an explanation for the observations that we see in the Earth?

One similarity we observed between the experimental and natural systems was how much seismic energy was released for events of different size. And the other one was the intermittency of the fracture’s growth. When there is a little bit of viscosity in the fluid, the fracture sticks for a while and then pops a little bit before it progresses. Sticks for a while, then pops. And these irregular pops are what has been observed in the natural system.

The evolution of the rupture, the slow-moving, fracturing in the lab was as intermittent and as irregular as what we would see in nature. So it looks like the overall evolution style was similar.

JG: This result shows that it’s all about the role of water — fracturing rock and squishing water into it. If you look at these rocks, it’s very clear that they’re full of veins. Many times there’s a black rock but it has all these white squiggly lines through it that very likely formed as fluids squirted into opening fractures.

This study connects those fluid-filled veins to the observed seismicity. They always say that invoking fluids is a geophysicist’s last resort: If you don’t know how to explain something, say, ‘Oh, it must have been the fluids.’ And so I was skeptical. But this makes me a bigger believer in fluids.

Why use a 3-D printed model for a process that occurs in the Earth?

JG: In the Earth you can measure the seismic waves at the surface, even though they’re being generated way down. But you can never see the crack. These processes occur many, many miles beneath the surface, and you’ll just never see them. The only time you actually see this environment is that sometimes these rocks that are buried miles down just naturally rise up to the surface over millions of years. This is what the geologists call “exhumed.” And you can see they have all these little fractures in them that have been filled with water and minerals and other stuff. But it’s long after the fact — you didn’t see them form, you only see the aftermath.

The experiment in the lab was a way to try to simulate this, so that you could see everything as it was happening. This allowed us to see the cracks form and connect that to the seismic signals we detect at the surface.

What do you think is most exciting about this result?

MD: It’s exciting to see a new demonstration of how the tectonic tremors we observe at the surface could be deep hydraulic fractures in which cracks form and open due to pressurized fluids. As geophysicists, we just assume that the tectonic movements are shear, or sliding motion between two solid objects. But we show experimentally that hydraulic fracture is consistent with the geological record.

For more information contact Denolle at mdenolle@uw.edu and Gomberg at gomberg@usgs.gov.

Watch: Researchers Brad Lipovsky and Marine Denolle explain how fiber-optic cables can be used to sense ground motion. Credit: Kiyomi Taguchi/UW

The fiber-optic cables that travel underground, along the seafloor and into our homes have potential besides transmitting videos, emails and tweets. These signals can also record ground vibrations as small as a nanometer anywhere the cable touches the ground. This unintended use for fiber-optic cables was discovered decades ago and has had limited use in military and commercial applications.

A 91̽�� pilot project is exploring the use of fiber-optic sensing for seismology, glaciology, and even urban monitoring. Funded in part with a $473,000 grant from the M.J. Murdock Charitable Trust, a nonprofit based in Vancouver, Washington, the new 91̽��Photonic Sensing Facility has three decoder machines, or “interrogators,” that use photons traveling through a fiber-optic cable to detect ground motions as small as 1 nanometer.

“Fiber-optic sensing is the biggest advance in ground-based geophysics since the field went digital in the 1970s,” said principal investigator , a 91̽��assistant professor of Earth and space sciences. “The 91̽��Photonic Sensing Facility and its partners will explore this technology’s potential across scientific fields — including seismology, glaciology, oceanography and monitoring hydrology and infrastructure.”

The new center — the largest in the United States and the first of its kind in the Pacific Northwest — is among a handful of research hubs around the world that are beginning to explore fiber optics for sensing ground motion. This approach to monitoring could expand the amount of seismic data by thousands of times.

For now, one of the three 91̽��interrogator machines is hooked up to a “dark fiber,” or unused cable, that runs between the 91̽��campuses in Seattle and Bothell. The researchers will soon also connect to a similar underwater cable across Alaska’s Cook Inlet to sense volcanic, oceanic, glacial and tectonic systems there. The other equipment will be used for temporary deployments.

When the ground vibrates — due to a heavy truck, construction work, or an earthquake — the seismic waves travel out from the source like ripples on a pond. When a seismic wave reaches the fiber-optic cable, the cable stretches very slightly, and that disrupts photons that are naturally reflected back to the source. The researchers can detect this disruption in the returning light waves and determine where the cable was disturbed.

The technique is known as “distributed acoustic sensing,” or DAS, because the system is spread out and can be used to monitor both sound waves and ground motion.

The same technology can also record more gradual motions. Lipovsky, who studies glaciers, and 91̽��graduate student carried equipment up to Easton Glacier on Mount Baker to monitor the rate of surface melt. The team installed a cable and used an interrogator to see how much snow was melting on the glacier.

In other pilot projects, 91̽��researchers with the Pacific Northwest Seismic Network are exploring uses for seismology, including earthquakes, volcanoes and landslides. 91̽��oceanographers will use fiber-optic cables connecting to a seafloor observatory to monitor ocean faults and even eavesdrop on whales. 91̽��civil engineers will study whether this technology could monitor traffic collisions or building and bridge infrastructure.

The facility will include semi-permanent observatories in Seattle and other unused “dark” fibers, including a cable that runs to Whidbey Island. The team also plans to lay cables for temporary field deployments at Mt. Rainier and is exploring projects farther afield at a fjord in Greenland and at McMurdo Station in Antarctica.

“We’re getting to the ‘smart Earth’ concept, where we can listen to the Earth,” said , a 91̽��assistant professor of Earth and space sciences. “This technology allows seismic sensing to go to places you could not go before — where it was too hard, or too expensive, to deploy sensors. The other aspect that’s new is a density of sensors beyond what we had before.”

Today’s seismometers record ground motion at a single point, whereas fiber-optic cables take measurements at many points along the cable — the test cable has 15,000 data channels. Denolle will use computing and machine learning to make sense of this new mountain of seismic data.

“In seismology, our data used to be just wiggles,” Denolle said. “This is the first time we can get 2D images, and even videos, of data streaming in.”

The grant was awarded in late 2021. Researchers have used the funds to hook up and test the equipment last spring, and a data-visualization room on campus is coming soon.

“Thanks to the M.J. Murdock Charitable Trust’s support, the 91̽��is the first university to acquire so much equipment for this technique,” Lipovsky said. “This is in the pilot experiment stage, and we are excited to see where it goes.”

Other funders are the 91̽��and the UW-based Pacific Northwest Seismic Network.

For more information contact Lipovsky at bpl7@uw.edu and Denolle at mdenolle@uw.edu.