Another Look at Plate Tectonics

Posted on June 12, 2016 by marcia

Research suggests major changes to geology textbooks

Posted by TW on June 11, 2016

A new research of the Earth’s crust and upper-mantle suggests that ancient geologic events may have left deep ‘scars’ that can come to life to play a role in earthquakes, mountain formation, and other ongoing processes on our planet.

This changes the widespread view that only interactions at the boundaries between continent-sized tectonic plates could be responsible for such events.

A team of researchers from the University of Toronto and the University of Aberdeen used super-computers to create models that indicate that former plate boundaries may stay hidden deep beneath the Earth’s surface. These multi-million-year-old structures, situated at sites away from existing plate boundaries, may trigger changes in the structure and properties at the surface in the interior regions of continents.

“This is a potentially major revision to the fundamental idea of plate tectonics,” says lead author Philip Heron, a postdoctoral fellow in Russell Pysklywec’s research group in U of T’s department of Earth sciences.

A new map of Earth’s ancient geology

Heron and Pysklywec, together with University of Aberdeen geologist Randell Stephenson have even proposed a ‘perennial plate tectonic map’ of the Earth to help illustrate how ancient processes may have present-day implications.

“It’s based on the familiar global tectonic map that is taught starting in elementary school,” says Pysklywec, who is also chair of U of T’s department of Earth sciences. “What our models redefine and show on the map are dormant, hidden, ancient plate boundaries that could also be enduring or “perennial” sites of past and active plate tectonic activity.”

To demonstrate the dominating effects that anomalies below the Earth’s crust can have on shallow geological features, the researchers used U of T’s SciNet – home to Canada’s most powerful computer and one of the most powerful in the world – to make numerical models of the crust and upper-mantle into which they could introduce these scar-like anomalies.

A proposed perennial plate tectonic map. Present-day plate boundaries (white lines), with hidden ancient plate boundaries that may reactivate to control plate tectonics (yellow lines). Image credit: Russell Pysklywec, Philip Heron, Randell Stephenson.

Simulating yesterday’s continents

The team essentially created an evolving “virtual Earth” to explore how such geodynamic models develop under different conditions.

“For these sorts of simulations, you need to go to a pretty high-resolution to understand what’s going on beneath the surface,” says Heron. “We modeled 1 500 kilometers across and 600 kilometers deep, but some parts of these structures could be just two or three kilometers wide. It is important to accurately resolve the smaller-scale stresses and strains.”

Using these models, the team found that different parts of the mantle below the Earth’s crust may control the folding, breaking, or flowing of the Earth’s crust within plates — in the form of mountain-building and seismic activity – when under compression.

In this way, the mantle structures dominate over shallower structures in the crust that had previously been seen as the main cause of such deformation within plates.

“The mantle is like the thermal engine of the planet and the crust is an eggshell above,” says Pysklywec. “We’re looking at the enigmatic and largely unexplored realm in the Earth where these two regions meet.”

An Earth in hibernation

“Most of the really big plate tectonic activity happens on the plate boundaries, like when India rammed into Asia to create the Himalayas or how the Atlantic opened to split North America from Europe,” says Heron. “But there are lots of things we couldn’t explain, like seismic activity and mountain-building away from plate boundaries in continent interiors.”

The research team believes their simulations show that these mantle anomalies are generated through ancient plate tectonic processes, such as the closing of ancient oceans, and can remain hidden at sites away from normal plate boundaries until reactivation generates tectonic folding, breaking, or flowing in plate interiors.

“Future exploration of what lies in the mantle beneath the crust may lead to further such discoveries on how our planet works, generating a greater understanding of how the past may affect our geologic future,” says Heron.

The research carries on the legacy of J. Tuzo Wilson, also a U of T scientist, and a legendary figure in geosciences who pioneered the idea of plate tectonics in the 1960’s.

“Plate tectonics is really the cornerstone of all geoscience,” says Pysklywec. “Ultimately, this information could even lead to ways to help better predict how and when earthquakes happen. It’s a key building block.”

Source: University of Toronto

from: http://thewatchers.adorraeli.com/2016/06/11/research-suggests-major-changes-to-geology-textbooks/

Ontario, Canada – Methane Gas Eruption

Posted on June 20, 2015 by marcia

6/20/2015 — Major Geologic movement in Ontario Canada — Methane Gas Geyser bursts from the ground

June 20, 2015 Michael Janitch

A large burst of naturally occurring methane has occurred in Lambton Shores, Ontario Canada, located about 80 miles Northeast of Detroit along the shores of Lake Michigan.

Appearing more like a violent geyser eruption at Yellowstone super-volcano, this large emission of methane caught locals off guard — as this is not ‘normal’ by any means.

Officials are saying this is a ‘natural’ burst of gas from the ground, and have issued a local state of emergency – warning people to keep away from the area.

_________

Methane bursts are a worst case scenario according to professionals like the Arctic Methane Emergency Group (AMEG).

Scientists have warned we would start seeing these types of methane emissions in sub-tundra areas now that the Post Glacial Rebound Effect is taking hold in earnest.

See more on AMEG here:

http://ameg.me/

_________

Natural gas geyser at Indian Hills golf course

http://www.lakeshoreadvance.com/2015/06/17/natural-gas-leak-at-indian-hills-golf-course

“Indian Hills golf course staff have posted an update regarding the eruption of natural gas this week. Earlier this week the course was closed because naturally occurring gases had been observed being released from the ground in a localized area of the golf course. There continues to be no risk to the public outside of the site. The monitoring and testing will continue. The declared localized emergency remains in effect.

” Here is our understanding at this time. We cannot allow anyone on the golf course until we know that the situation is stable and no gas is leaking from the ground. We have all the required survey’s and tests lined up to take place today, tomorrow and over the weekend and into the start of next week. We hope to reopen by next weekend and should be able to have clear answers to exactly what happened.

“As of 10am on Friday things are looking almost normal which is allowing us to do further tests that will ensure the publics safety.
Thanks for everyones understanding of the situation.”

Lambton Shores Deputy Mayor Cook stated “The Municipality is continuing to work with the Kettle and Stony Point First Nation, as the owners of the golf course in conjunction with experts in this area.” Residents are being asked to stay away from the immediate area until advised that the situation has been resolved.

The public may call 2-1-1 for any updates on the situation.”

________

Cause of natural gas bubbles in Lambton Shores thought to be natural

http://www.theobserver.ca/2015/06/18/cause-of-natural-gas-bubbles-in-lambton-shores-thought-to-be-natural

“Municipal officials in Lambton Shores declared a “localized state of emergency” Thursday, one day after a natural gas leak at a local golf course bubbled and released methane gas.

Doug Cook, the town’s deputy mayor, announced the state of emergency for the Indian Hills Golf Course and surrounding subdivision following a meeting of the Municipal Emergency Control group.

Gas has continued to leak into the air since Wednesday morning, and with no indication of when it might stop.

“We’re hoping it will dissipate in the near future,” Cook told The Observer. “There may be more radical steps to take if not, but at this point, there’s not much we can do.”

Firefighters and Lambton OPP responded to reports shortly before 8 a.m. Wednesday from a nearby First Nations group of a strange odour coming from a creek.

The golf course was evacuated when the leak was discovered, and access to Indian Hill Trail West remains restricted, said Const. Travis Parsons, the OPP’s community services and media relations officer.

Cook said the evacuation was a precautionary measure and there is no risk to the public outside the gas leak site.

The cause of the leak is under investigation and is assumed to be naturally occurring gas venting to the surface. If that’s the case, it would be a rare incident since natural gas is usually found in pockets deep into the ground.

Natural gas, used as an energy source for heating, cooking, and power generation, is flammable when it mixes with air at certain concentrations.

Union Gas accompanied the firefighters to the site and determined the leak was indeed natural gas and contained methane, according to Andrea Stass, Union Gas’ manager of media relations. The utility company does not have any natural gas pipelines in the area, she added.

Representatives from the Ministry of the Environment and Ministry of Natural Resources are working in tandem to monitor the leak, but are not responsible for testing or determining the cause of the gas bubbles.

“Our focus is making sure the sampling work is done to determine the cause,” said environment ministry spokesperson Kate Jordan. “Once we have that or further information, that will really help us to determine what the appropriate next steps are.”

That responsibility falls to the Kettle and Stony Point First Nation who technically own the land. It also falls within the municipality. As such, the First Nation has hired a consultant to determine where the gas is coming from.

The environment ministry did a review of the area for any possible sources of methane, but found nothing, Jordan said.

While there is a commercial sewage treatment plant on the golf course that sends treated “effluent” back to the creek, the ministry concluded “there is no indication that the sewage treatment plant or its effluent could be contributing to the methane release.”

The ministry also determined there is no possibility that the methane would present a health risk to people outside the immediate area, Jordan said. The municipality’s drinking water is safe.

“While signs may point to this being a naturally occurring gas leak, this has not been confirmed definitively,” Jordan said.

But Cook said with no possible sources of man-made pollutants releasing the methane, the consensus and “best opinion” is the gas leak is natural.

He added he had never heard of a naturally occurring gas leak before. Stass from Union Gas said she had heard of one other case in over 15 years working with the Chatham-based utility.

Lambton Shores, the First Nation and its consultant, as well as Ministry of the Environment officials are meeting again Friday. Until then, the state of emergency remains in effect and the public is advised to avoid the area.”

from: http://dutchsinse.com/

New Findings RE: Earth’s Core

Posted on February 28, 2015 by marcia

Scientists find oddly behaving ‘inner-inner core’ at Earth’s center

Using the coda waves from earthquakes, geologists have discovered that our planet’s core isn’t quite what we thought it was.

by Michael Franco

The newly discovered core at the center of the Earth has a different polarity than its surrounding core, represented by the purple lines. Lachina Publishing Services

Though the seismic waves from earthquakes are best known for their destructive capabilities, in the hands of geologists, they can be powerful tools of discovery. A research team at the University of Illinois has just used the rumbles from quakes to more closely examine the inner core of our planet, and what they found there was quite a surprise. It seems there’s another core inside the inner core that measures about half its diameter.

What demarcates this “inner-inner core” is that the iron crystals it contains are oriented on an east-west axis, unlike the iron crystals in the “outer-inner core” which organize along a north-south axis.

“The fact that we have two regions that are distinctly different may tell us something about how the inner core has been evolving,” Xiaodong Song, a professor of geology at UI who worked on the project with visiting postdoctoral researcher Tao Wang, said in a University of Illinois report about the findings. “For example, over the history of the Earth, the inner core might have had a very dramatic change in its deformation regime. It might hold the key to how the planet has evolved.”

While multiple components of the inner core have been suggested before, this is the first time the difference in polarity has been noted. “Indeed, the layering of the inner core has been suggested more than 10 years ago, at shallow depths of the inner core and at deeper parts of the inner core as well,” Song told Crave. “Everyone assumed before the crystal alignment was north-south. But here we found alignment in the inner-inner core to be nearly east-west.”

If all this inner and inner-inner talk sounds confusing, perhaps a quick geology refresher is in order. The Earth consists of three layers: the crust where we live; the mantle, a layer of scalding-hot liquid rock; and the core. The core consists of a liquid outer core containing mainly nickel and iron and a solid inner core made up mostly of iron. Even though the inner core is even hotter than its surroundings, the intense pressure at the Earth’s center means the inner core is unable to melt and remains solid, according to a National Geographic entry about the topic.

And now we can add another layer to our Earth’s composition: the inner-inner core, which is still mostly solid iron, but has a different polarity than the substance surrounding it.

In “unearthing” the inner-inner core, the research team relied on seismic sensors that pick up the waves that penetrate the planet after an earthquake hits, known as the quake’s coda. “The earthquake is like a hammer striking a bell; much like a listener hears the clear tone that resonates after the bell strike, seismic sensors collect a coherent signal in the earthquake’s coda,” the report says.

“It turns out the coherent signal enhanced by the technology is clearer than the ring itself,” said Song. “The basic idea of the method has been around for a while, and people have used it for other kinds of studies near the surface. But we are looking all the way through the center of the Earth.”

The researchers’ findings were published in the journal Nature on Monday.

from: http://www.cnet.com/news/theres-a-newly-discovered-core-inside-our-earths-core-and-it-behaves-oddly/

Tectonic Plate Movement Faster than Before

Posted on September 21, 2014 by marcia

Tectonic Plates Moving Faster: Study September 12, 2014

This aerial view of the San Andreas Fault shows how an untold number of slips have altered the landscape.

Scientists say they have found that Earth’s tectonic plates are now moving faster than at any other point in the last 2 billion years.Plate tectonics is the prevailing geologic process that shapes the planet.

It triggers most of the world’s strongest earthquakes and many volcanic eruptions, along with building mountains and moving continents.

While earlier research seemed to reveal that the massive tectonic plates are actually slowing down as Earth’s core cools, New Mexico Institute of Mining and Technology geochemist Kent Condie and colleagues say they have evidence of faster plate movements.

Writing in the journal Precambrian Research, the team says they looked at how often new mountain belts form when plates collide, and compared it to magnetic data from volcanic rocks.

That allowed them to determine where the rocks formed and how quickly the continents had moved.

Photo: U.S. Geological Survey

from: http://www.earthweek.com/2014/ew140912/ew140912a.html

Quake Proof Balancing Rocks

Posted on April 22, 2012 by marcia

ysterious Balancing Rocks Resist Quakes’ Shakes

Andrea Mustain, OurAmazingPlanet Staff Writer

Date: 22 April 2012 Time: 02:19 PM ET

A Precariously Balanced Rock, or PBR.
CREDIT: James Brune

SAN DIEGO — In the western San Bernardino Mountains, near the highway that links Los Angeles and Las Vegas, scientists recently discovered a geological mystery: colossal rocks perched in precarious poses right next door to the San Andreas Fault.

It’s not the rocks’ balancing act that is perplexing, said Lisa Grant Ludwig, a scientist who presented this puzzle to colleagues this week here at the annual meeting of the Seismological Society of America. It’s how the rocks have managed to stay that way with such an aggressive maker of powerful earthquakes just a few miles away.

Rocks with seemingly acrobatic balance are seen all over the world. Meteorological and geological forces wash away the material around them, leaving the giant rocks balancedlike a top. There’s even a term for them: Precariously Balanced Rocks, or PBRs for short, said Ludwig, an assistant professor at the University of California, Irvine.

“When you start to get into seismically active areas there are fewer and fewer,” Ludwig told OurAmazingPlanet. “And you don’t expect to see them right next to active faults —and you don’t, generally.”

Still standing

In fact, PBRs are used to verify earthquake hazard maps. “Quite some time ago it was recognized that wherever you see these things, it’s an indication there haven’t been a lot of really strong earthquakes because they haven’t been shaken down,” Ludwig said.

That’s what makes the San Bernardino PBRs so very strange. There are two pockets of more than a dozen of the gracefully balancing rocks, and some are only 4 miles (7 kilometers) from the fault.

Ludwig said that when a colleague brought her pictures of the rocks — and asked how they could possibly withstand the earthquakes that tear along the San Andreas Fault — she had to go see them for herself.

“I have spent most of my career documenting large earthquakes on the San Andreas Fault,” Ludwig said. “I could rock some of [the PBRs] with my hand.”

Seismic mystery

Subsequent dating research revealed that the rocks had been standing in their positions for millennia — in some cases as long as 18,000 years. “That’s a long time for something that is so close to a big fault,” Ludwig said.

It’s not clear why violent shaking has apparently spared the two small pockets near the fault where the rocks still stand. “I think it shows an area of complexity in the fault rupture,” Ludwig said, “and that is what a lot of my colleagues seem to agree on in the discussion.”

She said it’s something that researchers will be pursuing next. “We don’t have a good explanation,” she said.

from: http://www.livescience.com/19840-mysterious-balancing-rocks.html

Rio Grande Rift Earthquake Potential

Posted on January 12, 2012 by marcia

Some earthquakes expected along Rio Grande Rift in Colorado and New Mexico, new study says

January 12, 2012

Enlarge

(PhysOrg.com) — The Rio Grande Rift, a thinning and stretching of Earth’s surface that extends from Colorado’s central Rocky Mountains to Mexico, is not dead but geologically alive and active, according to a new study involving scientists from the University of Colorado Boulder’s Cooperative Institute for Research in Environmental Sciences.

“We don’t expect to see a lot of earthquakes, or big ones, but we will have some earthquakes,” said CU-Boulder geological sciences Professor Anne Sheehan, also a fellow at CIRES. The study also involved collaborators from the University of New Mexico, New Mexico Tech, Utah State University and the Boulder-headquartered UNAVCO. The Rio Grande Rift follows the path of the Rio Grande River from central Colorado roughly to El Paso before turning southeast toward the Gulf of Mexico.

Sheehan was not too surprised when a 5.3 magnitude earthquake struck about 9 miles west of Trinidad, Colo., in the vicinity of the Rio Grande Rift on Aug. 23, 2011. The quake was the largest in Colorado since 1967 and was felt from Fort Collins to Garden City, Kan.

Along the rift, spreading motion in the crust has led to the rise of magma — the molten rock material under Earth’s crust — to the surface, creating long, fault-bounded basins that are susceptible to earthquakes, said Sheehan, a study co-author and also associate director of the CIRES Solid Earth Sciences Division. The team studied the Rio Grande Rift region to assess the potential earthquake hazards.

Using Global Positioning System instruments at 25 sites in Colorado and New Mexico, the team tracked the rift’s miniscule movements from 2006 to 2011. “Questions we wanted to answer are whether the Rio Grande Rift is alive or dead, how is it deforming and whether it is opening or not,” said Sheehan.

The high-precision instrumentation has provided unprecedented data about the volcanic activity in the region. Previously, geologists had estimated the rift had spread apart by up to 2 inches or 5 millimeters each year, although the errors introduced by the scientific instruments were known to be significant. “The GPS used in this study has reduced the uncertainty dramatically,” Sheehan said.

Using the latest high-tech instrumentation, the scientists found an average strain rate of 1.2 “nanostrain” each year across the experimental area, the equivalent of about one-twentieth of an inch, or 1.2 millimeters, over a length of about 600 miles. “The rate is lower than we thought but it does exist,” Sheehan said.

The researchers also found the extensional deformation, or stretching, is not concentrated in a narrow zone centered on the Rio Grande Rift but is distributed broadly from the western edge of the Colorado Plateau well into the western Great Plains. “The surprising thing to come out of the study was that the strain was so spread out,” Sheehan said.

Results of the study are published in the January edition of the journalGeology.

The team plans to continue monitoring the Rio Grande Rift, probing whether the activity remains constant over time, said lead study author Henry Berglund of UNAVCO, who was a graduate student at CU-Boulder working at CIRES when he completed this portion of the research. Also, the team may attempt to determine vertical as well as horizontal activity in the region to tell whether the Rocky Mountains are still uplifting or not, Berglund said.

“Present-day measurements of deformation within continental interiors have been difficult to capture due to the typically slow rates of deformation within them,” Berglund said. “Now with the recent advances in space geodesy we are finding some very surprising results in these previously unresolved areas.”

As far as the potential for future earthquakes in the region, the study’s results are unequivocal, however. “The rift is still active,” Sheehan said.

The new study also is co-authored by CU-Boulder Associate Professor and CIRES Fellow Steven Nerem, Frederick Blume of UNAVCO, Anthony Lowry of Utah State University, Mousumi Roy of the University of New Mexico and Mark Murray of New Mexico Tech.

Provided by University of Colorado at Boulder

from: http://www.physorg.com/news/2012-01-earthquakes-rio-grande-rift-colorado.html

Bolivia’s Inflating Volcano

Posted on October 20, 2011 by marcia

Planet Earth – SCITECH

Rapidly Inflating Volcano Creates Growing Mystery

By Andrea Mustain

Published October 20, 2011

Noah Finnegan

How long has this been going on? Uturuncu, a Bolivian volcano that is inflating at an incredible rate.

Should anyone ever decide to make a show called “CSI: Geology,” a group of scientists studying a mysterious and rapidly inflating South American volcano have got the perfect storyline.

Researchers from several universities are essentially working as geological detectives, using a suite of tools to piece together the restive peak’s past in order to understand what it is doing now, and better diagnose what may lie ahead.

It’s a mystery they’ve yet to solve.

Uturuncu is a nearly 20,000-foot-high (6,000 meters) volcano in southwest Bolivia. Scientists recently discovered the volcano is inflating with astonishing speed.

“I call this ‘volcano forensics,’ because we’re using so many different techniques to understand this phenomenon,” said Oregon State University professor Shan de Silva, a volcanologist on the research team.

Researchers realized about five years ago that the area below and around Uturuncu is steadily rising — blowing up like a giant balloon under a wide disc of land some 43 miles (70 kilometers) across. Satellite data revealed the region was inflating by 1 to 2 centimeters (less than an inch) per year and had been doing so for at least 20 years, when satellite observations began.

“It’s one of the fastest uplifting volcanic areas on Earth,” de Silva told OurAmazingPlanet.”What we’re trying to do is understand why there is this rapid inflation, and from there we’ll try to understand what it’s going to lead to.”

The peak is perched like a party hat at the center of the inflating area. “It’s very circular. It’s like a big bull’s-eye,” said Jonathan Perkins, a graduate student at the University of California, Santa Cruz, who recently presented work on the mountain at this year’s Geological Society of America meeting in Minneapolis.

Scientists figured out from the inflation rate that the pocket of magma beneath the volcano was growing by about 27 cubic feet (1 cubic meter) per second.

“That’s about 10 times faster than the standard rate of magma chamber growth you see for large volcanic systems,” Perkins told OurAmazingPlanet.

However, no need to flee just yet, the scientists said.

“It’s not a volcano that we think is going to erupt at any moment, but it certainly is interesting, because the area was thought to be essentially dead,” de Silva said.

Uber-Uturuncu?

Uturuncu is surrounded by one of the most dense concentrations of supervolcanoes on the planet, all of which fell silent some 1 million years ago.

Supervolcanoes get their name because they erupt with such power that they typically spew out 1,000 times more material, in sheer volume, than a volcano like Mount St. Helens. Modern human civilization has never witnessed such an event. The planet’s most recent supervolcanic eruption happened about 74,000 years ago in Indonesia.

“These eruptions are thought to have not only a local and regional impact, but potentially a global impact,” de Silva said.

Uturuncu itself is in the same class as Mount St. Helens in Washington state, but its aggressive rise could indicate that a new supervolcano is on the way. Or not.

De Silva said it appears that local volcanoes hoard magma for about 300,000 years before they blow — and Uturuncu last erupted about 300,000 years ago.

“So that’s why it’s important to know how long this has been going on,” he said.

To find an answer, scientists needed data that stretch back thousands of years — but they had only 20 years of satellite data.

Volcano rap sheet

“So that’s where we come in as geomorphologists — to look for clues in the landscape to learn about the long-term topographic evolution of the volcano,” Perkins said.

Perkins and colleagues used ancient lakes, now largely dry, a

Historic Evidence of Collapse of Canary Islands Volcano

Posted on October 6, 2011 by marcia

Scientific paper reveals massive historic Tenerife volcano flank collapse

Last update: October 6, 2011 at 10:57 am by By Armand Vervaeck

Written by Dave Petley
Dave Petley is the Wilson Professor of Hazard and Risk in the Department of Geography at Durham University in the United Kingdom. His blog provides a commentary on landslide events occurring worldwide, including the landslides themselves, latest research, and conferences and meetings.

This post provides a brief review of a new paper that describes a newly discovered catastrophic landslide deposit in Tenerife.
One of the most intriguing but poorly understood landslide types is that of thevolcanic flank collapse. In a volcanic flank collapse, the side of a volcano fails, usually catastrophically, generating a landslide. These slides can be really big – tens or even hundreds of cubic kilometers – and they can travel huge distances along the sea floor. Such failures grabbed attention a few years ago due to the potential (overstated, in my opinion) for generating a catastrophic tsunami.

However, we understand such phenomena really poorly. There are a number of reasons for this, principally that:
a. They occur rarely (globally about one in every 25 years on average), so actually recording one is a challenge
b. the remains tend to lie in a very dispersed state on the floor of the deep ocean. Fieldwork at 4 km water depth remains difficult, even if you are really good at holding your breath.

However, it is one particular aspect of these landslides that remains elusive, but is crucially important. This is the trigger of the collapse event (i.e. of the landslide itself). Numerous mechanisms have been proposed, including sea level change, climate change, hydrothermal pressure, intrusion of volcanic material, and various others. It has proven very difficult to ascertain the importance of each of these. This is an important question if we are to reliably estimate the hazard associated with future potential collapses.

In a paper published in Geology this month, Harris et al. 2011 report a very interesting find on the island of Tenerife, one of the Canary Islands. This is the remains of an ancient collapse event on the south-eastern part of Cañadas volcano. The landslide deposit, which is up to 50 metres thick, has been mapped across a large area – 90 square kilometres – and this is just the onshore component of the mass, which may extend another 50 km offshore. The deposit consists of a classic debris avalanche material, with large (typically up to 12 m long axis), shattered blocks in a highly disrupted, unsorted matrix. This is typical of a highly energetic, very large collapse event. Intriguingly, in the upper part of the deposit some fluviolacustrine (water/lake) sediments are found in the remains of hollows, indicating that in the aftermath of the landslide shallow lakes formed on the surface, presumably as a result of blockages created by the landslide. Associated with the landslide deposit are the remains of pyroclastic flows.

Chromographics Institute

Color + Art = Healing

Tag Archives: Geology