Bergzerreißung EarthCache

Gravity deformation extending deep into the mountain slopes

Gravity deformation extending deep into the mountain slopes, subsidence or sag is a slow, large-scale movement of rock masses under the influence of gravity. Consequences and characteristics of a subsidence are crevices, double ridges, valley thrust, leveling and valleys parallel to the slope with areas sloping inwards. Mountain fissures can pose a danger for rockfalls or landslides.

When a mountain ruptures, fissures in the solid rock open up in the upper part of a slope according to the given structure of the rock or as fissures parallel to the slope, giving the slope a torn appearance. The word "subsidence" describes both the process that leads to the opening of fissures, but also the result. The movements occur very slowly and can take centuries.

The term "Bergzerreißung" (gravity deformation extending deep into the mountain slopes) was formed in the 20th century by the Austrian geologist Otto Ampferer, who, along with Alfred Wegener, was one of the founders and describers of the theories of continental drift and plate tectonics, which are important for understanding the changes in our earth's crust, mountain formations, the formation of eartquakes and tectonic processes.

Subsidence or sag near Nockalmstrasse

The otherwise mostly quiet landscape character of the Nockberge is interrupted in this area next to the Nockalmstrasse by an unique striking and rugged terrain. Due to the tectonic movements of the earth's crust, the brittle limestone and dolomite rock was deeply fissured here in the past and broken down into partial blocks. In addition, over the course of millions of years, the stream flowing at the bottom of the slope has carved a deep V-shaped valley with steep sides. As a result, the supporting base of the slope was gradually removed. The partial blocks of the rock that predominates here, in the central part Paleozoic limestone and dolomite, now follow the slope and slowly move downhill in a staggered manner. This subsidence is clearly visible here in open or rubble-filled, staircase-like cracks in the rock and in the saber growth of the trees in the adjacent area. During the construction of the Nockalmstrasse, this area had to be bypassed for geological reasons in order to ensure a safe route.

To log the Earthcache, you must answer the following questions via message:

1.) What is the name of the stream that cut the steep V-valley through its erosion?
2.) Estimate the width and dephth of the central gash created by the subsidence (sag)!
3.) Do you think this mountain rift will change in the future? If yes or no, why?
4.) Optional: Post a photo of yourself or your GPS near the header coordinates along with your log entry.

Once you have sent your message with the answers, you can log the Earthcache as found. There is no need for log permission! If something is wrong, I'll let you know via message. Have fun!

The most exciting way to learn about the Earth and its processes is to get into the outdoors and experience it first-hand. Visiting an Earthcache is a great outdoor activity the whole family can enjoy. An Earthcache is a special place that people can visit to learn about a unique geoscience feature or aspect of our Earth. Earthcaches include a set of educational notes and the details about where to find the location (latitude and longitude). Visitors to Earthcaches can see how our planet has been shaped by geological processes, how we manage the resources and how scientists gather evidence to learn about the Earth. To find out more click HERE.