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Get to Know a Scientist Emeritus—Gary Fuis

This is the eleventh in a series of Get to Know posts highlighting and celebrating the contributions of exemplary Scientists Emeriti.  Their work, experience, and contributions are essential to the mission of the USGS. 

Gary brings more than 50 years of experience with the USGS and the judgement and expertise he has developed over his long career to everything he does as an emeritus. This includes not only his scientific pursuits, but also his work in improving the USGS and the Earthquake Science Center by building relationships with colleagues and responding to numerous requests for assistance or advice. As a master at organizing large “active-source” seismic experiments, with interpretations guided by a profound geologic understanding and intuition, Gary’s sage and thoughtful advice and guidance are solicited by a wide range of colleagues inside and outside the USGS. We are especially excited to see the stream of recent manuscripts and maps Gary is producing as an emeritus, including those from legacy data sets collected early in his career. Gary continues to be a valuable resource and superb colleague as an emeritus, as he mentors younger scientists (and center directors!) and continues his geophysical studies of the San Andreas Fault (SAF) and related faults in California.

Gary has employed seismic surveying techniques like those used for resource exploration to identify active faults in the subsurface. He is currently leading an effort to evaluate the structure and dip of the SAF in the San Francisco Bay area. The dip of the fault can strongly affect the severity of future ground shaking and the “connectedness” of faults, which in turn controls the size of future earthquakes. The group he leads working on this effort is comprised of colleagues from two USGS science centers and a research institute in Germany. Gary's ongoing studies of the seismotectonics of California are valuable, both for their fundamental scientific advances, and for the mitigation of earthquake hazards. As an insightful scientist, a valued colleague, and a friend to many of us, as he has been for his entire career, Gary continues to make tremendous contributions to the Earthquake Science Center as an emeritus!

Stephen Hickman, PhD
Director, Earthquake Science Center


Holding detonation cord during loading of explosive into a drill hole in the Imperial Valley, CA
Holding detonation cord during loading of explosive into a drillhole in the Imperial Valley, CA. 

What attracted or brought you to work for USGS in the first place?

I was a National Association of Geoscience Teachers (NAGT) intern in the first summer of the program (1966) and chose to go to the USGS Branch of Astrogeology in Flagstaff, AZ. The U.S. was ramping up for the lunar landing program, and there was nothing more exciting. In a more general sense, I had since high school wanted to work with the USGS, as it was the premier earth science organization in the world, and I had fallen in love with geology. I wanted to do science but work outdoors. During the summer internship, I did not work directly with astronauts, but was introduced to explosives which were used to create craters in a cinder field that astronauts could drive their moon buggy through. Working with explosives became a habit for the rest of my career.

I started grad school at Caltech the following fall. My advisor was Gene Shoemaker, who I had met in Flagstaff. Gene started me off looking at possible Earth analogs to lunar features, including circular structures and flat plains. My first summer in grad school, I mapped a volcanic center for ashflow tuffs in Western Arizona and also a nearby circular structure. Ashflow tuffs were thought to be a candidate for some of the flat plains on the Moon, and the circular structure was analogous to meteorite impact craters that we knew existed on the Moon. So far, no ashflow tuffs have been discovered on the Moon. The circular structure, when mapped in detail for my PhD thesis, turned out to be an erosional crater on top of a structural dome that had been created by a potassic mafic intrusion. So, none of my analog studies really applied to features on the Moon. Oh, well. We learned a lot about the Earth instead.

Gary Fuis installing panel for future seismograph installation, Montague Island, Alaska.
Gary Fuis installing panel for future seismograph installation, Montague Island, Alaska.

How long did you work at USGS before you retired and how long have you been an Emeritus?

41.6 years full time and another four years part-time as a grad student. I retired in 2012, so I have been an emeritus for a little over eight years. Altogether, I have been with the Survey for over 53 years in one capacity or another.

What was your last title/position at USGS before you retired and became an Emeritus?

Research Geophysicist.

What Science Center do you answer to as an Emeritus?

The Earthquake Science Center in Menlo Park, California.

Slinging explosive into the lake at the foot of the Sheridan glacier, Chugach Mountains, near Cordova, Alaska
Slinging explosive into the lake at the foot of the Sheridan glacier, Chugach Mountains, near Cordova, Alaska.

What are you most proud of during your career with the USGS? OR describe a highlight of your career.

I have led seven major active-source transect investigations, including one across Alaska from the Pacific to Arctic oceans. These transects consisted of a series of explosions recorded on our new portable seismographs, from which we interpreted crustal structure. We have investigated crustal structure in locations from Imperial Valley, CA, to Prudhoe Bay, AK. These datasets most likely cannot be repeated given the increasing difficulty in getting permits and environmental clearance. Everywhere we went we met the unexpected in our findings.

My most quoted findings are in the Imperial Valley, CA. But, I think my most favorite finding was in southern Alaska. A block, called the Yakutat terrane, is being carried northward into the Alaskan continent atop the Pacific Plate. Its behavior upon hitting the continent is different, depending on its thickness. Where it is thin enough, it remains glued to the Pacific Plate as the Pacific Plate subducts beneath Alaska. The buoyancy of this double-plate thickness causes it to extend far inland underneath Alaska, and it shuts off subduction-caused volcanoes above. Where it is too thick, it is scraped off the Pacific Plate into a rapidly rising coastal range of mountains. The Pacific Plate continues to subduct without the Yakutat terrane in this location and goes down steeply, giving rise to the largest subduction-caused volcanoes in North America. A tear has developed in the subducting plate between these two different behaviors. The 1964 M 9.2 Great Alaska Earthquake originated near this tear and ruptured southwestward initially along the interface between the double-plate thickness and the overlying continent. Alaska is tough terrain in which to do field work, and we often needed to use helicopters to get the job done. The whole thing was an adventure—it was the first time anyone had looked at Alaskan crust on a continental scale.

The USGS is special because we had trained explosives experts. Commonly, we detonated explosions in drill holes, but we also shot in lakes in which we could feel assured of minimal damage to life and the environment. In southern Alaska, we used lakes on top of or in front of glaciers. In northern Alaska, we had to avoid killing long-lived fish by working in shallow, fishless lakes that froze to the bottom in the winter. One disadvantage of working in Alaska is that we worked all day long in the constant daylight. Many colleagues do not appreciate how much work this actually is and the level of difficulty in working in areas with few roads.

Gary Fuis, beginning first summer of field work in Arizona in 1967
Gary Fuis, beginning first summer of field work in Arizona in 1967.

What led you to decide to become an Emeritus?

Unfortunately, my wife’s health. She needed my help, and I wanted to spend more time with her.

What exciting research or service activities are you currently working on, and what are you planning for the near future?

Just before I retired in 2012, I had conducted a large active-source investigation of the Imperial Valley, CA, for the second time. (The first time was in 1979, but instrumentation had been vastly improved since then, and many questions remained.) When I retired I had a huge data set to analyze, along with my many colleagues. So, I was busy with that until about 2017. Since then, I have re-investigated subsurface structure in the vicinity of the 1989 magnitude 6.9 Loma Prieta earthquake in the Bay Area. Our findings in the Imperial Valley indicated that the San Andreas Fault (SAF) is neither vertical nor planar. Early studies of the Loma Prieta rupture had concluded that the rupture could not have occurred on the SAF. The SAF was assumed to be vertical and planar, and the Loma Prieta rupture dipped moderately southwest and did not project to the surface trace of the SAF. We have shown that the rupture was most likely indeed on the SAF, and resembles ruptures on the SAF in the Imperial Valley.

What do you enjoy and appreciate the most about being an Emeritus?

Gary Fuis outreach
Gary Fuis using a foam rubber model to demonstrate, what happens to the Earth’s crust in the Los Angeles region when it is squeezed by plate-tectonic stresses at a Science Exposition in San Francisco. The display is called “Come Squeeze LA”. The gray block in the center (San Gabriel Mountains) moves sideways and upward along the San Andreas fault, modeled by a sheet of teflon, when squeezed.

Being able to continue working on earth structure. Mother Nature is more entertaining than any fiction ever written! I also like maintaining friendships with my colleagues of many years, who have become like a family.

What type of mentoring or outreach activities do you currently undertake as an Emeritus?

Since retirement, I have worked with two college graduates and two post graduates, analyzing the data we have collected. Pretty much, that’s it, especially now with the restrictions of the pandemic.

Have you had any great career mentors, and if so, what made them great?

My first advisor at Caltech in 1966 was Gene Shoemaker, father of the USGS astrogeology program in Flagstaff. He could get a crowd excited about a grain of sand, so great was his enthusiasm for earth science.

What is your best advice for early and mid-career scientists? 

Advocacy in science is not a good thing. There are always multiple interpretations of a data set. If you only have one interpretation, generate another (good) one. It is okay to state a preferred interpretation, but alternates should also be mentioned. Advocacy may be okay in policy and politics, but not in science. The history of science is full of advocacy problems.

Don’t be afraid of collaborating with others, especially experts who you may not know. You do not and can not know everything, and others are incredibly valuable in filling in the gaps and moving you forward in your research. I have spent my career attaching myself to smart people and doing projects. I have collaborated with some experts for 25-30 years.

Don’t focus on administrative or bureaucratic issues. Obey the rules but focus on your research. 

If you could give your 18-year-old self, one piece of advice, what would it be?

Follow your dream and be stubborn about it. You won’t get a second chance.

If you could travel on a time machine to any era in time, what would it be and why?

Eocene or Oligocene. The rise of the Rocky Mountains.

Where did you travel last, domestically or internationally?

Domestically, to the annual meeting of the Southern California Earthquake Center, my favorite meeting. Internationally, to Potsdam, Germany, to work with colleagues at the GeoForschungsZentrum, an institution similar to the USGS.

What was the last (or favorite) book you read?

How to Build a Habitable Planet, by Langmuir and Broecker. This is a summary of the history of the universe, solar system, and Earth from Big Bang through the Holocene. It is so good and complete that it is used as a textbook in some earth science courses.

What is one characteristic that you believe every good research scientist should possess?

Curiosity. Also, determination to find the answer to any question that arises in the course of research.

How are you spending your time during the pandemic?

Working on three papers and participating in two virtual geoscience conferences (GSA and AGU).

Gary Fuis plumbing the depth of a frozen lake for future emplacement of explosives
Gary Fuis plumbing the depth of a frozen lake for future emplacement of explosives.

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