The impact at El'gygytgyn crater

Moment of impact: As the asteroid hits the ground with a velocity of several tens of kilometers per second, a shock wave is generated that penetrates radially into the ground and compresses the rocks.

Contact/compression stage
Christian Koeberl, University of Vienna

 

 

 

 

 

 

 

 

 

A few seconds after the impact: The shock wave proceeds into the ground and a release wave moves back toward the surface, causing material to flow downward and outward, which leads to the excavation of the crater. Early in the impact phase, both the projectile and some rocks are vaporized and melted, lining the cavity of the crater.

Contact/compression stage
Christian Koeberl, University of Vienna

 

 

 

 

 

 

 

 

 

 

 

A few tens of seconds after the impact: The maximum crater depth is reached. Shocked, broken (brecciated) and melted rocks are thrown into the air. Some of these ejecta are deposited outside the crater, some fall back into the crater. The crater floor starts to rebound, leading to a central uplift formation.

Contact/compression stage
Christian Koeberl, University of Vienna

 

 

 

 

 

 

 

 

 

 

A few minutes after the impact: The central uplift has formed and is being buried by the cooling melt rocks and breccias that are falling back to Earth. The steep crater rim starts to collapse and slide into the crater, leading to a wider and shallower crater. The formation of the crater structure is over after just a few minutes. Breccia and debris continue to fall back into the crater for a few hours.

Contact/compression stage
Christian Koeberl, University of Vienna

 

 

 

 

 

 

 

 

 

A few years after the impact: The crater floor is now covered by melt rocks and fallback breccia (dark red), and rain and groundwater have formed an early crater lake (blue), and some early lake sediment deposition has begun. The crater rim has completed its collapse.

Contact/compression stage
Christian Koeberl, University of Vienna

Tuesday, July 20, 2010 - 07:30