By Lindsey Hernandez, GSA Science Communication Intern, Masters Student Ohio State University

When geoscientists assess volcanic hazards, they usually focus on large, explosive volcanoes with historic eruptions that have caused major damage in populated areas. However, Amanda Clarke, a volcanologist at Arizona State University, has focused her recent work on a different kind of volcano—cinder cones—which she calls “little volcanoes with big stories”.

Cinder cones are small, unimposing volcanoes. They periodically erupt ash and spatters of basalt—a dark-colored lava with low silica—to build small, symmetrical cones. These types of eruptions are typically much lower energy and less destructive than the likes of Mount St. Helens in Washington, USA, or Tambora in Indonesia.

However, while leading a workshop at Sunset Crater near Flagstaff, Arizona, Clarke’s attention was drawn to evidence that an unusually large and explosive eruption occurred at this cinder cone in 1085 AD. This eruption blanketed the area with ash, resulting in the abandonment of Sinagua Indians settlements, as detailed in historic accounts. This magnitude of eruption is considered rare for cinder cones, but Clarke has recognized that these eruptions might be more common than previously thought.

Sunset-Crater_Arizona Office of Tourism
Sunset Crater Volcano – Credit: Arizona Office of Tourism

Clarke’s work on Sunset Crater has inspired her to look at other cinder cones around the world for evidence of highly explosive eruptions. Tecolote, a cinder cone in Pinacate Volcanic Field in northwest Mexico, has been fruitful in this respect. A large, explosive eruption occurred here approximately 27,000 years ago, throwing ash more than 10 kilometers from the vent.

Both Sunset Crater and Tecolote have explosively erupted with energy on par with large eruptions in Central America and Indonesia. While Sunset Crater and Tecolote are not located in heavily populated areas, other cinder cone fields are common in the western United States, in states such as California and Nevada. Clarke speculates that an eruption of this size today could disrupt air traffic and impact nearby communities. Therefore, understanding why and how large, explosive eruptions occur at cinder cones has been a focus of her work.

Amanda Clarke is a volcanologist at the Arizona State University School of Earth and Space Exploration. She co-convened the session ‘Basaltic Volcanism on Earth and Beyond: Exploring the Physical Controls on Eruptive Styles and Associated Deposits’ on September 25th at the 2019 Geological Society of America Annual Meeting in Phoenix, Arizona.


The GSA Science Communication Internship was a program offered at the GSA Annual Meeting in Phoenix, AZ, designed for student attendees interested in science communication as a possible alternative career path.  Interns were paired with GSA’s Science Communication Fellow in order to gain experience in making science clear and exciting, under the tutelage of a professional writer.  Students were assigned to conduct interviews with presenters at the meeting and to compile summaries capturing the significance of the presenters’ work for a non-technical audience.  Media assignments and mentoring were useful learning experiences and exposure opportunities for students seeking to expand their knowledge into geoscientific reporting.