On the Subject of Geology

[lovemarie]

Collision Mountain Ranges Video

Continental collision is a phenomenon of the plate tectonics of Earth that occurs at convergent boundaries. Continental collision is a variation on the fundamental process of subduction, whereby the subduction zone is destroyed, mountains produced, and two continents sutured together. Continental collision is known only from this planet and is an interesting example of how our different crusts, oceanic and continental, behave during subduction.




https://youtu.be/xmIM-QCZHMw



-credits to geologypage.com

[lovemarie]

NASA releases photos of 8,000-year-old mysterious geoglyphs in Kazakhstan

Posted on November 3, 2015 by Abner Macolor



NASA released photos of the strange huge earthworks in Kazakhstan called Steppe Geoglyphs

The mysterious geoglyphs were discovered by an amateur archeologists in 2007 using Google Earth

The 8,000-year-old geoglyphs were reported to the scientific community only in 2014

Massive ancient earthworks formed by human-made mounds, divots and trenches discovered in 2007 that have baffled researchers as to who made them and for what purpose are now the object of National Aeronautics and Space administration (NASA) investigation.
 
NASA recently released some photos of the mysterious huge earthworks, which are called Steppe Geoglyphs, to the public’ signaling the start of the space agency’s involvement in the investigation of the enormous patterns etched into the barren grassland or steppe of Kazakhstan.

The patterns which range in size from 300 to 1,300 feet are believed to be 8,000 years old. Most of the geoglyps were made from mounds of dirt only 3 feet high and about 30 feet wide. The patterns that look like crop circles, squares, and swastikas can only be seen 430 miles from the sky.

Dismissing radical theories and speculations that they were made by or connected to aliens, the discoverer of the geoglyphs, Kazakh economist and amateur archeologists Dimitriy Dey, said “’I don’t think they were meant to be seen from the air.”

He believes the colossal structures were used by ancient settlers in the area as “horizontal observatories to track the movements of the rising sun as seen on Earth.”


 
The Steppe Geoglyphs were discovered by Dey in 2007 while using Google Earth in search for satellite images for pyramids and other similar configurations in Kazakhstan. He found at least 260 of these huge earthworks.

The geoglyphs was reported to the scientific community in 2014 during an archaeology conference.

Persis B. Clarkson, an archeologist at the University of Winnipeg, told New York Times that the discovery of the ancient earthworks could dramatically change the current understanding of nomadic Stone Age cultures.

“The idea that foragers could amass the numbers of people necessary to undertake large-scale projects, like creating the Kazakhstan geoglyphs, has caused archaeologists to deeply rethink the nature and timing of sophisticated large-scale human organization as one that predates settled and civilized societies,” he said.

NASA has directed its astronauts on board the International Space Station to take pictures of the Kazakhstan region where the geoglyphs are located. The space agency is also using satellites from Digital Globe to take images of some of the strange formations from space.

Compton J. Tucker, the NASA scientist who provided the images of the geoglyphs said, “I’ve never seen anything like this. I found it remarkable,” adding that NASA was “proceeding to map the entire region.”


 
Source :New York Times, Daily Mail, Science Alert, Tech Times

[jamesbond]

now they are all interested on the accidental find by an amateur archeologist... like what the article said, it's not crop circles or sqaures or swastikas, man made structure din pero nobody knew what they are for... mere theories and speculations na lang... sana may concrete findings sila later on....

[lovemarie]

‘Hidden earthquake’ discovery challenges tsunami early-warning systems


Tsunami warning/evacuation sign from the Chile coast.
Credit: Dr. Stephen Hicks



Seismologists at the University of Liverpool studying the 2011 Chile earthquake have discovered a previously undetected earthquake which took place seconds after the initial rupture.

This newly discovered phenomena which they called a `closely-spaced doublet' presents a challenge to earthquake and tsunami early warning systems as it increases the risk of larger-than-expected tsunamis in the aftermath of a typical subduction earthquake.

In a study published in Nature Geoscience, University researchers analysed in detail the seismic wave recordings from 2 January 2011 when an earthquake of magnitude 7 occurred in Chile along the plate boundary separating the subducting Nazca plate from the South American continent.

 
They discovered that just 12 seconds later and 30 km further offshore, a second rupture of a similar size, which was un-detected by national and global earthquake monitoring centres, occurred along an extensional (pull-apart) fault in the middle of the South American plate beneath the Pacific Ocean.

Liverpool seismologist, Professor Andreas Rietbrock, said: "Real-time global seismic monitoring and early warning events have come a long way and it is possible for a magnitude 5 or greater earthquake to be detected within a matter of minutes. Therefore, it is striking that an earthquake with magnitude close to 7 was effectively hidden from our standard monitoring systems."

"Previous doublet events have been documented in subduction zones before, but such instantaneous triggering of large ruptures at close distances has no known precedent. Such triggered events dramatically complicate potential earthquake impact assessments and tsunami early warning systems as the risk of a larger than expected tsunami is higher following a typical subduction earthquake."

Dr Stephen Hicks, who was part of the research team, said: "We believe that seismic waves travelling outward from the first rupture immediately shook up and weakened the shallower second fault, causing the hidden rupture. Scientists believe that the overlying plate at collisional plate boundaries is broken up on a large scale and contains networks of faults. It is plausible that similar closely-spaced doublets may occur elsewhere around the Pacific Ring of Fire. "

Professor Rietbrock added: "This work challenges the commonly-held notion that slip during large earthquakes may only occur along a single fault. The result was surprising as there was no indication of such a complicated rupture from global earthquake monitoring systems. "

"Our findings present a concern for tsunami early warning systems. Without real-time monitoring of seismometers located close to the fault, it is possible that tsunami and shaking hazard from future subduction earthquakes may be underestimated."

As part of the University's Liverpool Earth Observatory, seismologists are installing a seismic network in Southern Peru in close collaboration with the Geophysical Institute of Peru.

This area along the South American continental margin has the potential for a large magnitude 8+ earthquake and it is important to understand the associated seismic and tsunami hazard.

Reference:
Stephen P. Hicks, Andreas Rietbrock. Seismic slip on an upper-plate normal fault during a large subduction megathrust rupture. Nature Geoscience, 2015; DOI: 10.1038/ngeo2585

Note: The above post is reprinted from materials provided by University of Liverpool.