Fire Earth

Earth is fighting to stay alive. Mass dieoffs, triggered by anthropogenic assault and fallout of planetary defense systems offsetting the impact, could begin anytime!

Posts Tagged ‘Earth’s crust’

Chile Earthquake Broke Earth’s Crust

Posted by feww on March 10, 2010

Chile Earthquake: ‘A Complicated Fracture’

‘A jumping rupture process’

The Chilean M8.8 megaquake that struck offshore Maule region on 27 February,  was a “complicated rupture process” scientists at the GFZ German Research Center for Geosciences say.

Quakes of this  magnitude break the entire Earth’s crust, they said. “After closer analysis of the seismic waves radiated by this earthquake during the first 134 seconds after start of the rupture, the researchers came to the conclusion that only the region around the actual epicenter was active during the first minutes. In the second minute the active zone moved north towards Santiago. After that the region south of Concepción became active for a short time. This rupturing trend agrees well with the distribution of the aftershocks during the following three days, as observed by the GEOFON-measuring network of the GFZ up to 03.03.2010.”


Rupture Propagation After Southern Chile’s Maule Earthquake. © GFZ. Click Image to Enlarge.

In 1960, the largest ever instrumentally-recorded earthquake, which  measured magnitude 9.5, originated at Valdivia, south of the Maule region. “The quake of 27 February connects directly to the rupture process of Valdivia,” said Professor Jochen Zschau, Director of Earthquake Risk and Early Warning Section at the GFZ. “With this, one of the last two seismic gaps along the west coast of South America might now be closed. With the exception of one last section, found in North Chile, the entire earth crust before the west coast of South America has been ruptured within the last 150 years.”

The Nazca plate which forms a part of the Pacific Ocean Floor moves eastwards at about 70mm per year, subducting the South American plate.  Thus producing very powerful earthquakes in the region. “In the course of about one century, the Earth’s ruptures completely in a number of strong quakes from Patagonia in the South to Panama in the North. Even Darwin reported, in his diary, of the strong earthquake in Concepción on 20 February 1835 and the resulting Tsunami.”


Chile Earthquake History. © GFZ. Click Image to Enlarge.

GFZ researchers have reportedly studied the collision of the Nazca plate and the South American Plate since 1994. “As a result of numerous expeditions and measuring campaigns in this area this Potsdam Helmholtz Centre avails of the probably the most dense data record on such a subduction zone. “Within the framework of the DFG Priority Programme “Deformation processes in the Andes”, and with the Geotechnology Project TIPTEQ we have just been able to collect a unique data record for the southern part of the Andes” says Professor Onno Oncken, Director of the Department Geodynamics and Geomaterials at the GFZ, and leader of these studies. The current quake puts us in the position to precisely compare the tectonics before and afterwards, a unique situation both internationally and in Earth science.”

GFZ is operating the Plate Boundary Observatory (PBO) in northern Chile, which they’ll hand over to Chilean researchers on 15 March 15, 2010.

Related Links:

Posted in chile tsunami, Nazca Plate, Pacific Ring of Fire, South American plate, tsunami | Tagged: , , , , , , | 2 Comments »

Climate Change: For what you’re about to receive…

Posted by feww on September 16, 2009

It’s what you wished for!

Scientists Echo More Hazards of Global Warming You Probably Didn’t Know Existed, or Cared Much

More of the human enhanced geological hazard are being spelled out as scientists scratch hard, going beyond textbooks.

Global Climate Change will trigger violent geological activity, but little is known about the effects. Larger, deadlier quakes? “Orchestral” volcanic eruptions? Giant glacial slides/ landslides? More frequent Jumbo tsunamis? Methane Burps?

Those are just a few of the items on the menu, which you have already ordered, and will have to pay for.

Sit tight and see how you fare on the deadly white-knuckle ride as global warming changes the earth’s crust. No need to fasten your seat belt because it won’t help.

Glacial meltwater lake in Greenland
“WHOI glaciologist Sarah Das stands in front of a block of ice that was raised up 6 meters by the sudden drainage of a meltwater lake in Greenland. (Photo by Ian Joughin, UW Polar Science Center)” Image may be subject to copyright.

Global warming may cause more deadly quakes and tsunamis

“Climate change doesn’t just affect the atmosphere and the oceans but the earth’s crust as well. The whole earth is an interactive system,” Professor Bill McGuire of University College London was reported as saying, at the first major conference on the changing climate’s effects on geological hazards.

“In the political community people are almost completely unaware of any geological aspects to climate change.”

“When the ice is lost, the earth’s crust bounces back up again and that triggers earthquakes, which trigger submarine landslides, which cause tsunamis,” said McGuire.

According to the Toba catastrophe theory a supervolcanic event at Lake Toba ( Sumatra, Indonesia) plunged the Earth into a mini-ice-age lasting several thousand years (70,000 to 75,000 years ago). The explosion, classified as “mega-colossal,” ejected about 2,800 km³ of volcanic matter into the atmosphere, the impact of which reduced the world’s human population to about 10,000, possibly a mere 1,000 breeding pairs, creating a bottleneck in human evolution. [The theory was proposed in 1998 by Stanley H. Ambrose of the University of Illinois at Urbana-Champaign.]

In more recent times, about 3,600 years ago, the Minoan eruption of Thera (Santorini), a major catastrophic volcanic eruption (VEI = 7, DRE = 60 km3), which was the second largest volcanic events on Earth in recorded history, destroyed most of the island of Thera, and contributed to the collapse of the Minoan culture. It also caused significant climatic changes in much of the Northern Hemisphere, for example, failure of crops in China.

NASA’s Jet Propulsion Laboratory researcher Tony Song has warned about the enormous power of  “glacial earthquakes.” Millions of tons of  glacial ice, cracked by hydrofractures caused by the lubricating effect of the meltwater from supraglacial lakes, slide downward from great heights (in West Antarctic the ice sheet is about a mile high) like  massive landslides.

“Our experiments show that glacial earthquakes can generate far more powerful tsunamis than undersea earthquakes with similar magnitude,” said Song.

“Several high-latitude regions, such as Chile, New Zealand and Canadian Newfoundland are particularly at risk.” [Having discovered an additional dozen or so nasty surprises, FEWW issued a travel warning to would be visitors to New Zealand months ago!]

Although ice sheets are disintegrating much more rapidly than previously thought, he noted, glacial earthquake tsunamis were “low-probability but high-risk.” [For now, anyway, but the odds are rapidly changing for the worst.]

Volcanoes can spew vast amounts of ash, sulphur, carbon dioxide and water into the upper atmosphere, reflecting sunlight and sometimes cooling the earth for a couple of years. But too many eruptions, too close together, may have the opposite effect and quicken global warming, said U.S. vulcanologist Peter Ward.

“Prior to man, the most abrupt climate change was initiated by volcanoes, but now man has taken over. Understanding why and how volcanoes did it will help man figure out what to do,” said Ward.

Speakers were careful to point out that many findings still amounted only to hypotheses, but said evidence appeared to be mounting that the world could be in for shocks on a vast scale.

McGuire says man-made CO2 emissions must be stabilized within about the next five years, to avoid a nightmare of which geological hazards are only a small part. What he didn’t say is where he got his 5-year “grace period” from because the tipping point was reached about 3 years ago, according to FEWW “EarthModel.”

“Added to all the rest of the mayhem and chaos, these things would just be the icing on the cake,” he said. “Things would be so bad that the odd tsunami or eruption won’t make much difference.”

Related Links:

Posted in geological hazards, geophysical hazards, Global Warming hazards, human evolution, Minoan eruption of Thera | Tagged: , , , , , , , , , | 2 Comments »

Climate Change, Earthquakes, Volcanic Eruptions

Posted by msrb on January 1, 2009

Climate Change IS Increasing the Frequencies of Major Geological Events

There will be more earthquakes, volcanic eruptions and landslides both on the land and sea floor

In a study first published on the web in 2004, NASA and United States Geological Survey (USGS) scientists found that retreating glaciers in southern Alaska may lead to more earthquakes in future.

“The study examined the likelihood of increased earthquake activity in southern Alaska as a result of rapidly melting glaciers. As glaciers melt they lighten the load on the Earth’s crust. Tectonic plates, that are mobile pieces of the Earth’s crust, can then move more freely.” [The study appeared in the July 2004 issue of the Journal of Global and Planetary Change.

Jeanne Sauber of NASA’s Goddard Space Flight Center and Bruce Molnia, a research geologist at USGS used NASA satellite and global positioning instruments, together with computer models, to analyze tectonic plates movements in relation to melting glaciers in Alaska.

“Historically, when big ice masses started to retreat, the number of earthquakes increased,” Sauber said. “More than 10,000 years ago, at the end of the great ice age, big earthquakes occurred in Scandinavia as the large glaciers began to melt. In Canada, many more moderate earthquakes occurred as ice sheets melted there,” she added.

“Southern Alaskan glaciers are very sensitive to climate change, Sauber added. Many glaciers have shrunk or disappeared over the last 100 years. The trend, which appears to be accelerating, seems to be caused by higher temperatures and changes in precipitation.” the report said.

They discovered that a tectonic plate under the Pacific Ocean in southern Alaska was pushing toward the coast, creating very steep mountains. “The high mountains and heavy precipitation are critical for glacier formation. The colliding plates create a great deal of pressure that builds up, and eventually is relieved by earthquakes.”

The sheer weight of massive glaciers that rest atop active seismic areas help minimize plate tectonic movements. “But, as the glaciers melt and their load on the plate lessens, there is a greater likelihood of an earthquake happening to relieve the large strain underneath.”

Major earthquakes occur as a result of plate tectonic movements.

The researchers believe that a 1979 earthquake in southern Alaska, dubbed the St. Elias earthquake, which  measured 7.2 on the Richter scale, occurred  because the local glaciers melted.

“Along the fault zone, in the region of the St. Elias earthquake, pressure from the Pacific plate sliding under the continental plate had built up since 1899 when previous earthquakes occurred. Between 1899 and 1979, many glaciers near the fault zone thinned by hundreds of meters and some completely disappeared. Photographs of these glaciers, many taken by Molnia during the last 30 years, were used to identify details within areas of greatest ice loss.”

“Field measurements were also used to determine how much the glacier’s ice thickness changed since the late 19th century. The researchers estimated the volume of ice that melted and then calculated how much instability the loss of ice may have caused. They found the loss of ice would have been enough to stimulate the 1979 earthquake.

The two scientists, Sauber and Molnia used data from global positioning system and NASA satellites as well as Shuttle Radar Topography Mission (SRTM) to document the glacier extent and topography.

“In the future, in areas like Alaska where earthquakes occur and glaciers are changing, their relationship must be considered to better assess earthquake hazard, and our satellite assets are allowing us to do this by tracking the changes in extent and volume of the ice, and movement of the Earth,” Sauber said. Source

“Climate change: Tearing the Earth apart?”

Bill McGuire, professor of Geophysical Hazards at University College, in an article in New Scientist, titled “Climate change: Tearing the Earth apart?” wrote:

“In the early 1970s John Chappell of the Australian National University in Canberra was the first to make the link between glacial advances and retreats and the rate of global volcanism. We now know that the warming that heralded the start of the current interglacial period around 10,000 years ago brought forth a burst of volcanic activity in Iceland, as melting ice caps reduced pressures on the magma chambers below. Allen Glazner of the University of North Carolina at Chapel Hill identified a similar pattern in eastern California over the past 800,000 years. Increased levels of volcanic activity are also recorded at mid-latitude ice-covered volcanoes in the Cascades Range of the US and in the Andes.”

“[I]t shouldn’t come as a surprise that the loading and unloading of the Earth’s crust by ice or water can trigger seismic and volcanic activity and even landslides. Dumping the weight of a kilometre-thick ice sheet onto a continent or removing a deep column of water from the ocean floor will inevitably affect the stresses and strains on the underlying rock.” McGuire said.

“Not every volcanic eruption and earthquake in the years to come will have a climate-change link…  Yet as the century progresses we should not be surprised by more geological disasters as a direct and indirect result of dramatic changes to our environment. The only saving grace is that a significant increase in volcanic activity would pump large volumes of sulphate gases into the stratosphere, which would cool the Earth’s surface and slow global warming, at least for a time. It’s a hell of a price to pay, though, for ignoring a phenomenon that could be far more easily sorted if we lived more considered and sustainable lives.” He said.

FEWW Team believes that aerial bombardment, nuclear tests, large scale urbanization, use of explosives for mining and similar activities, as well as human mobility also play  significant roles in increasing the frequencies of earthquakes, volcanic eruptions and land and sea-floor landslides.

Posted in Alaska quakes, Climate Change, plate Tectonic, seismic area, St. Elias earthquake | Tagged: , , , , | 9 Comments »