The USArray component of the NSF-funded EarthScope project ended its observational period in September 2021 and all remaining close-out tasks concluded in March 2022. Hundreds of seismic stations were transferred to other operators and continue to collect scientific observations. This website is now in an archival state and will no longer be updated. To learn more about this project and the science it continues to enable, please view publications here: and citations of the Transportable Array network DOI 10.7914/SN/TA.

To further advance geophysics support for the geophysics community, UNAVCO and IRIS are merging. The merged organization will be called EarthScope Consortium. As our science becomes more convergent, there is benefit to examining how we can support research and education as a single organization to conduct and advance cutting-edge geophysics. See our Joining Forces website for more information. The site will soon host the new EarthScope Consortium website.

A Continental-scale Seismic Observatory

Road Warriors

By Maia ten Brink


     Show the Transportable Array field engineers a map of the United States and ask them to point out where they’ve been. “I’ve been here,” they’ll say, sweeping a hand from California to Maine.
     They are carrying out one of the largest-scale science experiments in history. The USArray Transportable Array (TA) is a dense seismic network that records earthquakes to enable scientists to study the structure of Earth’s interior. The field engineers have installed more than 1700 seismic stations at 70-kilometer intervals across North America.
     In the taxonomy of road warriors, TA field engineers lie somewhere between truckers and cellular service providers.

Bob Pierce and Dan Knip's sleeping arrangement while
installing solar-powered equipment in Quebec in August 2012.

They work everywhere and nowhere. They live out of trucks and take-out containers.  They’re drive-by tourists who have seen almost every American city at a 70 kilometers’ resolution through a dusty windshield. Lone travelers, they haunt the tar, eating up the yellow lines, bumping along back roads, stomping around dude ranches, digging holes, and installing seismic instruments in backyards and pastures across the United States.
     The TA operates by rolling its 400 seismic instruments from west to east. The field crew deploy stations in one region of the country for two years, then remove them in order to re-deploy them elsewhere. Reusing the seismic instruments in this way requires a finely tuned schedule of operations and a lot of driving time. The construction and install guys—Mike Couch, Dean Lashway, and Bob Pierce—set up a central base in a small town for a few weeks and build surrounding stations in a spoke pattern. The service crew—Dan Knip, Doan Nguyen, and Howard Peavey—snake around the country, fixing up whichever stations have sent out distress signals or need to be drained of rain. Anthony Kim, who removes stations at the end of their tenure and prepares parts for the installers to re-use, mows along about 500 kilometers west of the construction crews.
     The job requires an unusual level of commitment: three weeks of travel every month, hours of highway transit carrying supplies between seismic stations, and long days of construction in remote locations. Many of the field crew come from a military background and are used to relocating frequently, but this lifestyle is even more transient than what they’re accustomed to. “Sometimes I don’t get home for a couple of months,” says Doan Nguyen, a soft-spoken older engineer from Washington State. Traditional family life proves challenging; none of the field crew has young children, and only a few are married. “The loneliness factor is high,” admits Dan Knip, whose job fixing broken TA stations means he doesn’t know where he’ll be each week. “I think if I were to fall into a hole in the ground, people wouldn’t know where I was for a month.”
Bob Pierce has been installing TA stations since the very beginning, April 2004. “I have a house in Albuquerque I haven’t lived in for about ten years,” he says. “I used to visit every few months, but not anymore.” He likes the reclusive nature of the job. He frequently disappears on camping trips between installs and won’t answer his phone. His colleagues once called the National Park Service to report him missing; turns out he was just off in the woods.


     The TA field engineers mostly work alone, coming together only for difficult installs, in particularly remote areas of Alaska and southern Québec, or for annual team meetings. The majority of their time is spent in solitude at the wheel.
     Drives between stations can be brutal. Pierce’s personal rule is that he finishes a station, gets to a hotel and has dinner, and the next day drives to wherever the next station is, no matter the distance. Knip rode around with Pierce for six weeks of training. “One day we drove 17 hours to get to the next station,” Knip says. “That guy has a work ethic.” Knip drives on average 240 kilometers per day, but his record was 1200 kilometers in one shot. “The miles are tough,” he says. “I find myself driving less per day than I did earlier in the project… Howard [Peavey], on the other hand, just this past month went from Socorro, New Mexico, to Oregon, fixed the station, and now is on his way to Maine. That’s an insane amount of driving.”
     During the long drives, Pierce plays language tapes and mouths along to Spanish and Italian pronunciations. His GPS, Francesca, sends him “a destra” and “a sinistra” instead of right and left. Knip listens to Jared Diamond audiobooks or ham radios with strangers 1000 kilometers away. Couch, Nguyen, and Peavey listen to nothing but the hum of the wheels.
     Knip says he has considered getting a pet to keep him company. “I stopped at a hardware store once and they had little baby ducks for farmers to buy. I thought I would take a duck along with me while I was working, but I realized that one day I would get to the hotel and forget him in the car or get out the site and forget about him and a wolf would eat him,” he says. “I thought about maybe I could grow carrots or something on top of the truck, have a garden in the box, so that as I’m driving down the highway the sun will grow the whole garden. But I haven’t done that either.”
     The field crew breaks the monotony of travel with little personal rituals. Pierce is on a quest to visit every Starbucks in the country. Knip tries to fish in every state. Anthony Kim keeps a stack of menus as souvenirs from his favorite meals. He’s been audited three times because the higher-ups can’t fathom how one person could spend $200 at mom-and-pop restaurants in rural towns. Pierce vouches for Kim’s formidable appetite. “He’d get a grocery bag, sometimes two, full of food. He’d have the full family-size cans of ravioli and Spaghetti-o’s,” Pierce says. “He’d sit in the passenger seat while I’m driving for like three hours, opening cans and eating and eating and eating and throwing the can in the back and eating and eating. Constantly.”

     “This is kind of a 24-hour-a-day job,” says Howard Peavey, a frenetic, graying New Mexican who has been known to fix stations with any material at hand, including a hockey stick and some duct tape. While he drives, he muses about which clues he missed while working on the last station or considers what to do at the next one. “When I wake up in the middle of the night, I’m usually back on the computer again,” reading statistics about broken stations and trying to diagnose what’s causing malfunctions.
     What keeps the field crew from burning out? Everybody credits the team mentality cultivated by TA’s manager, Bob Busby. “We are really fortunate to have him running the project,” says Knip.
     Juggling a team of field engineers, analysts, and researchers spread around the United States proves challenging, but Busby’s strategy is to focus on the daily logistical issues that crop up in the field. “Whenever somebody has a problem in the field or calls in from a remote location, they actually take priority over the people who are in offices,” he says.
     He credits the field crew’s resourcefulness and slight obsessiveness for a seismic array that delivers data of unprecedented quality. “A lot of my management style is to find skilled experts and grow their skill level outward to encompass more and more people, build variety of expertise, and let people try to do their job or improve the project from within,” he says.
     “I don’t want to go home without the job accomplished,” shrugs Nguyen, whose record of installing two to three seismic stations a day around New England has some of the other field crew members shaking their heads in disbelief.
     “There are a lot of rewarding, disciplined, interesting people,” says Knip. “So you get hooked up in a team that is really driven, and it starts to consume your thinking. I’ve had many important jobs where, at five o’clock, I would wash my hands and go back to my own life. I don’t do that here. You see this [work ethic] in all the guys… That’s Busby’s gift to the whole world. We are a bunch of kittens and he keeps us all herded without using a whip.”

     In October 2013, the TA turned 10 and the field crew finished installing the final phase of seismic stations along the Atlantic coast. The team comes together for a wrap-up meeting in Woods Hole, Massachusetts. The men look haggard. Many have driven straight from their last installs in Maine. They’re eager to hear what scientific discoveries their years of driving and digging had enabled—they joke that they had completed “PhDs in dirt.”
     During the science presentations, Knip stands at the back of the room; he’s been sitting in his truck for too long, he says. After three days of meetings and more social contact than he’s had in an entire year, he and the other field engineers return home for a mandatory month-long vacation. “My preference would be not to go somewhere,” says Knip. “Have a staycation.”