# @usgs on Instagram

- **Type:** Image
- **Original URL:** https://www.instagram.com/p/DE0bvSwgGzX
- **Gondola URL:** https://gondola.cc/posts/69013933-usgs-instagram
- **Thumbnail:** https://img.gondola.cc/tr:w-,h-,fo-auto/postThumbnails/158e150fdf.jpg
- **Posted:** 2025-01-14T20:23:30.000+00:00
- **Account Owner:** U.S. Geological Survey (USGS) (@USGS) — https://gondola.cc/USGS

## Caption

Worried about slipping on the ice? 

In Alaska, that's exactly what these USGS scientists study! Strike-slip fault systems shaped by tectonic forces, that is!

A strike-slip fault occurs when two massive chunks of the Earth's surface move, collide, and then slide past each other horizontally. The strike-slip fault system in Alaska shown here is covered in ice.

Scientists monitor this area closely since it has caused some of the biggest earthquakes ever recorded on U.S. soil, including a magnitude 7.9 earthquake in 2002. This massive event ruptured along the Denali-Totschunda fault system, rivaling California's San Andreas Fault in length and seismic significance.

In the Denali-Totchunda fault system, the Pacific Plate collides with North America, leading to significant seismic activity and shaping the state's dramatic landscape. The Denali fault, a major geological feature, shows evidence of millennia of stress and movement, moving roughly at a rate the width of a paper clip each year since the last ice age. These ongoing tectonic changes highlight Alaska's dynamic and evolving geology.

This area and the large 2002 earthquake remain key case studies for understanding strike-slip fault systems, seismic hazard mapping, and the powerful tectonic forces that shape our world.
 
❄️ Scientists examine the Denali fault trace on the Susitna Glacier to find matching ice surfaces to determine the amount of fault offset.
❄️ Scientist prepares to measure the offset of a crevasse on the Canwell Glacier.
❄️Scientist overlooks Canwell Glacier.

#SnowyScience

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## Tags

snowyscience

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