Finding faults: WWU faculty/student team travels overseas to study plate tectonics in India

Since 2023, WWU Assistant Professor of Geology Paul Betka has led students across the world and into the Himalayas. 

Betka’s mission: explore the planet’s largest active zone of subduction accretion, which happens to lie beneath the feet of more than 200 million people.

During India’s dry season in December, Betka and three students made the four-plane, 40-hour journey to Jorhat in the Indian state of Assam. There, the team met up with Betka’s research colleague Raghupratim Rakshit and a group of students from Jagannath Barooah University before beginning the long, winding road trip to the Lohit River Valley in Arunachal Pradesh, India.

Over the next ten days, the team examined crustal deformation associated with the Noa Dihing fault, a major structure that formed at the intersection of three tectonic plates: the Eurasian plate, the Burma Plate and the Indian plate.

The Indo-Burman Ranges of Bangladesh, northeast India and Myanmar are the planet’s largest example of active subduction accretion, where a tectonic plate descends beneath another, scraping off sediment and crustal materials and accreting them at the second plate’s edge, like a giant bulldozer piling up earth for 100s of kilometers. The Noa Dihing fault marks an important tectonic boundary where the accreted material between the Indian and Burma plates is also colliding with the Himalayan orogen between the Indian and Eurasian plates. 

By studying the Noa Dihing fault, Betka’s team hopes to understand how active fault systems associated with these tectonic plates evolve and how they interact with each other. 

It’s a process that can only be understood by putting boots to the ground, trekking through Indian jungles and wading through knee-deep river waters to directly observe and measure deformation associated with the faults.

“If you want to understand how these processes work, you have to go to the Himalayas,” Betka said.

Up the river and through the jungle

Geology senior Dena Chance of Seattle joined Betka’s team after working in his lab as a research assistant. It was her first time learning in the field.

“I went into this with zero expectations,” Chance said. “I did not know what I was getting myself into, and a lot of it was unexpected.”

She traveled alongside geology graduate students Jake Swartz of Madison, Alabama and Ceci Howes of Winnipeg, Canada, who previously traveled with Betka into the field last March.

While in India, the team stayed in a local family homestay, where they spent their mornings drinking red tea and listening to the bird-like chirps of gibbons hanging in nearby trees. After a breakfast of sabzi and eggs, Betka’s team and the Jagannath Barooah University students loaded into cars and drove into the field. 

The caravan followed a road along the Noa Dihing River, stopping to take measurements when they found an outcrop, exposures of bedrock or geologic formations that are visible due to soil and vegetation erosion.

Because the Arunachal Pradesh region is primarily a dense jungle, the best bedrock exposures are from fresh road cuts or river cuts, Betka said.

“There's a lot of infrastructure expansion in the northeastern ranges of India, and there are new road cuts everywhere,” Betka explained. “We can examine these road cuts to make first order measurements on the lithology — the rock type and the orientation — and if there are structures present, we measure them. That's how we collect our data.”

In order to find more hidden outcrops, Betka and his team would roll up their pants to their knees and wade through the local rivers that drain the mountains. 

“We were trekking up the river through the middle of the jungle,” Howes said. “I felt like I was in a movie — like Indiana Jones.” 

On the last day of their journey, Betka and his team set out on one final attempt to locate an outcrop the Noa Dihing fault. 

Because the fault is located in remote, difficult-to-reach areas of India, Betka’s research team was unable to access it during previous field excursions. Betka tried to reach the fault in 2024 by bushwacking through the jungle but ran out of daylight and was forced to turn around before reaching it.

Using Google Earth, Betka found a spot along a small river that had a promising outcrop.

After hours of wading through river waters and very little daylight left, the team feared they would soon have to turn back again. 

But when the team rounded a corner, a 100-meter-wide exposure of the fault zone greeted them.

“We all put our hands on our head like, ‘Oh my God, this is it’ and then, ‘Oh my God, we have no time left,’” Betka said. 

The team scrambled to take as many measurements of the exposure as possible, returning with a few dozen key fault plane measurements, Betka said.

"It was certainly enough data to characterize the sense of motion on the fault, identify the fault type and really recognize that this was a nice exposure of the Noa Dihing fault,” he said. “It was a great way to end the trip.”

Preparation, not prediction

Ask a geologist how we can predict when earthquakes will happen, and the answer will be simple: You can’t.

However, that doesn’t mean we can’t prepare for earthquakes, and studying the characteristics and movements of fault systems along the borders of tectonic plates helps us do just that.

“We can't predict when earthquakes are going to happen, and the key word there is ‘when,’” Betka said. “But what we can do is we can start to learn about how an earthquake might behave along particular fault systems.”

Studying how the Earth’s plates move and the geometry of Earth’s subsurface allows scientists to estimate the size of earthquakes a region can expect, which in turn informs hazard maps, building codes and disaster response plans.

“One thing I like to tell people when I'm describing the Assam region is that it's the land of superlatives,” Betka said. “We've got the Himalayan mountains, which are the biggest mountain range in the planet, and they're situated adjacent to the Bangladesh Ganges-Brahmaputra Delta — the biggest river system on the planet — and it has the potential to make the biggest earthquakes. And this is all in a region that has one of the highest population densities.”

The three tectonic plates that create the Himalayas are actively colliding and driving the formation of the mountains, Betka said. Because of this, the likelihood of earthquakes is strong, and recent studies of the region have predicted the potential for a large magnitude earthquake.

A large magnitude earthquake can destroy communities near the epicenter. In 1950, a magnitude 8.6 earthquake hit the Mishmi Hills in the northeastern tip of India. The quake caused significant damage in both India and neighboring Tibet. Approximately 1,500 deaths were reported in Assam and an additional 3,300 were reported in Tibet. It is the largest earthquake on record caused by a continental collision rather than subduction zone, and the 10th largest quake ever recorded.

“It's a critical intersection of active tectonic processes, population growth and development that is fascinating and important to understand better,” Betka said.

Finding the Noa Dihing fault allows Betka to measure its geometry to better understand how it moves — data that cannot be produced in a lab.

“The field is our laboratory. Nature has been conducting an experiment in the Himalayas about what happens when two plates collide for 55 million years,” Betka said.

When asked what could be learned from the field that couldn’t be learned in a lab, Howes, Swartz and Chance responded in unison: “A lot.”

“Geology is an applied science, so it’s hard to do any geology if you haven’t seen the rocks you’re studying,” Swartz said. “I wouldn't have a graduate project if I hadn't gone and done the field work that we did there.”

Because the Assam area is so remote, there hasn’t been much research into the Noa Dihing fault, Howes said.

Chance spent the entirety of fall quarter reading what research papers do exist to prepare for the trip, but her prep work paled in comparison to wading through the river in the jungle, she said.

“I remember having this moment where I was like, I literally think I learned more about the composition of each unit and the structure of this specific region in these past two days than I did over the whole quarter,” Chance said.

Dancing, singing and stargazing

When dark settled over the Assam region each day, Betka’s team returned to their homestay. 

The northeastern states are located in the far east of the Indian Standard Time zone, so it gets dark around 4 pm. “We developed a habit of stopping and looking at the stars on this one bridge as it got darker out before dinner, which was really wonderful,” Chance said.

The team would have a cup of tea, discuss what they saw in the field, and make a plan for the next day while enjoying dinner with the Jagannath Barooah University students.

After their first night of field work, Betka gave a lecture to the students summarizing the main takeaways from their time in the field that morning. When he finished, the students made a request: Could they sing for us?

 This prompted a talent show where the Jagannath Barooah students sang and taught Betka’s team the traditional Bihu Dance, forming a circle and beginning with a slower tempo that gradually builds momentum.

“Then, of course, they wanted us to perform, so they made us do karaoke,” Howes said. 

After Howes, Swartz and Chance sang a rendition of John Denver’s “Take Me Home, Country Roads,” the Jagannath Barooah students asked if there were any traditional American dances they could learn. 

“I was like, ‘OK, here's a very traditional American line dance!’” Chance said with a laugh. 

Betka plans to return to India with WWU students in March 2027. Learn more about his research at https://paulbetkageology.squarespace.com/

Mikayla King, ’17, covers the College of Science and Engineering and Woodring College of Education for University Communications. Reach out to her with story ideas at kingm24@wwu.edu.