JOINT BASE McGUIRE-DIX-LAKEHURST, N.J. - Unlike the buried bombs he faced in Iraq, the danger beneath the earth's shifting layers is quiet. Not explosive or sudden, but gradual.Sgt. 1st Class Timothy Kearns knows this.From 2003-2004, he was a combat engineer in Iraq responsible for "route clearance," a term that wasn't officially coined until later on. Now, he's a trainer for the 75th Training Division, but his life in Houston revolves around the science of substrata movements.This week, however, he's out of the big city trekking miles across swampy woods and somber range roads. He's been competing all week against the top Soldiers in the Army Reserve for the 2014 Best Warrior Competition. The competition is designed to evaluate the best of its Soldiers across various skills, from warrior knowledge to physical fitness and mental grit."I'm sore everywhere. My Achilles tendon hurts like crazy. I have blisters the size of these muffins on the bottom of my feet," he said, pointing at the rolls on his breakfast plate.That morning he had just finished 8 miles in less than 3 hours. Beneath his feet, however, the earth's layers might shift a few millimeters per year.Kearns is working toward his geology doctorate in sub-surface studies. He leads a team of graduate students, using geo-positioning technology to track the earth's movement beneath Houston's cityscape. With more than 2 million residents living across 600 square miles of land, those millimeters could lead to centimeters. Those centimeters could lead to fractures and instability to more than 360 high-rise buildings.Cracks in pipes and walls could result in millions of dollars worth of damage. His aim is to help prevent that. Kearns wouldn't discuss his thesis in detail, not until he's had a chance to defend it, but he alluded to the dangers of pulling water from the earth leading to potential shifts in the ground."There's something fascinating about natural science," said Kearns. "Understanding geology is sort of like understanding a crime scene."Being away from Houston has been rough for Kearns this week. Not just because of the miles, or the 4-hour sleep nights or even the 165-pound dummy lift, which Kearns carried with three other Soldiers for an entire mile."My professors generally say that if you take more than a Sunday afternoon off, then you're probably not going to make it through a Ph.D. program, or at least not the one we're in," said Kearns.Spending a week away from the University of Houston's campus might as well be a year sabbatical. He usually works from 7:00 in the morning to 10 at night.Even though Kearns' adviser is not a U.S. citizen, he has been extremely supportive of his military commitment. Dr. Guoquan Wang is a Chinese immigrant with U.S. residency who earned his Ph.D. from Peking University. Kearns refers to Dr. Wang as a friend and not just an adviser. Despite being on a stringent project schedule, Wang encouraged Kearns to participate in the Best Warrior Competition.According to Kearns, Wang appreciates the hard-working mentality of the military culture. In Wang's eyes, military discipline helped his professional studies. He selected Kearns specifically for the project manager job because of the leadership skills he learned in the Army."Before I joined the Army, my grades were awful. After I joined, I came back and I was on the dean's list almost every semester," he said. "It's really hard to tell exactly when my civilian life ends and my military life begins ... The Army instills in me a desire to become better than what I am every single day."The discipline and experience the Army provided also came with some consequences, however."I was so wound up when I got back from the war," he said.In Iraq, other dangers lay beneath the earth. Insurgent attacks threatened his life more than once. Fortunately for him, insurgents were inexperienced with improvised explosive devices back then. They were still new to the conflict."They buried the South African 155 (mm artillery round) so deep that when the blast went off, it went straight up into the air, and so it saved us from a lot of shrapnel. But I still remember pieces of ground hitting me in the hands," he said.As he shared his stories, it seemed as though Kearns couldn't escape the earth's ground. His combat uniform was covered in New Jersey dust from firing in the prone at the M-16 rifle range. The dirt clung to his clothes, made into a filmy paste from the ounces of sweat that had poured from his body on the ruck march."The most exciting thing is just being able to compete against the best of the best in the Army Reserve. It's really something to be able to test my skills against theirs," he said.When he had come back from Iraq, a college mentor from Sam Houston State University steered him toward an outlet that provided relief. In 2004, Kearns began training in Hapkido, which is a martial art that focuses on minimal, not brute, force. Hapkido allowed Kearns to shift the trauma of war away from his mind and body. He stuck with it for five years, earned his black belt, then elevated to Kendo, which is Japanese sword fighting.Kearns alluded to the parallel between these two disciplines of Army and Hapkido a few times. Soldiers are taught to kill from the early days of basic training. While Army warriors scream while penetrating the flesh of dummies with their bayonets, Hapkido empowers warriors with a quiet strength. It teaches to restrains violence in self-defense. Even with a sword in hand, Kendo is more of an art form than a kill strategy.That contrast extends to Kearns' double life of a Warrior Citizen: He moves with force and quickness as he trains to fight America's enemies throughout the world, yet he's cerebral and studious as he aims to keep the earth's gradual threats at bay.