Rockfall on EARTH Magazine

Lidar sheds light on roadside rockfall hazard

Mon, 17 Jul 2017 08:16:23 -0400

Rockfalls, like this one along Highway 198 in California, are a major hazard on many U.S. roadways. Credit: Tommy Lee Kreger, CC BY 2.0.

Rockfalls represent a significant hazard on many U.S. roadways that wind through steep terrain. But with money tight for roadside hazard mitigation, engineers are looking for more efficient ways to assess where and when unstable slopes could give way. In a new study, researchers suggest that lidar might be a cost-effective solution.

Down to Earth With: Yosemite's first park geologist Greg Stock

Tue, 02 Feb 2016 10:02:41 -0500

Stock and U.S. Geological Survey civil engineer Brian Collins download data to study how daily temperature variations affect granitic exfoliation prior to rockfalls. Credit: USGS/Valerie Zimmer.

A love of rock climbing led Yosemite National Park geologist Greg Stock, seen here on a cliff face at Glacier Point in Yosemite, into the field of geomorphology. Credit: Steven Bumgardner.

As a child growing up in the foothills of California’s Sierra Nevada Mountains, Greg Stock and his family took frequent trips to Yosemite National Park. One of his first memories is of hearing and seeing a giant rockfall tumble down the face of El Capitán. Today, Stock studies such rockfalls and how they impact safety in the area as the first park geologist employed at Yosemite.

Seismometers listen for falling rocks

Fri, 21 Aug 2015 11:48:06 -0400

Fresh debris lines part of Yosemite Valley after a rockfall. Credit: National Park Service.

Scores of natural rockfalls occur in California’s Yosemite Valley every year, often with little or no advance warning, posing hazards to people and infrastructure. In 1980, for example, a fall near Yosemite Falls killed three people and injured 19. Efforts to record and document rockfalls are rudimentary, relying only on eyewitness accounts and after-the-fact observations of fresh talus piles, which means many events are likely going unreported. In a new study, however, researchers interested in whether there’s a better way to monitor these events propose that seismic and infrasound sensors can help keep tabs on the granite slabs dropping from Yosemite’s cliffs.

Yosemite's cliffs in retreat

Mon, 20 Apr 2015 10:38:20 -0400

This past winter, two athletes grabbed the world’s attention as they climbed up the sheer walls of Yosemite National Park’s El Capitan. But some geologists are more concerned with what falls down these precipitous faces — namely, rocks. Park geologist Greg Stock has developed a history of rockfalls in Yosemite valley dating back 15,000 years, which reveals how its cliffs have crumbled since glaciers disappeared at the end of the last ice age.

Witnessing geology in action: A rockfall in the garden of the gods

Wed, 20 Nov 2013 09:09:45 -0500

A rock formation in the Garden of the Gods, N.M., before a rockfall. Mary Caperton Morton

The rock formation in the Garden of the Gods, N.M., after the rockfall. A white scar on the fin marks the site of the erosion. Mary Caperton Morton

The rockfall left a smattering of bright white rock all over the ground. Mary Caperton Morton

Mary Caperton Morton

Editor's Note: Traditionally, EARTH has published a "highlights" or "year in review" issue at the end of the year. This year, we decided to try a new approach: We asked our staff and some frequent contributors to write a short commentary on something that grabbed their attention in 2013. We gave everyone carte blanche. What follows is a collection of extremely varied, often very personal insights into how the planet impacted each individual. You can find some online this month, but for the full grouping, you'll have to buy the issue here or subscribe.