Cascadia Fault

All posts tagged Cascadia Fault

In 2011, an earthquake generated a devastating tsunami that was observed across the Pacific and caused tremendous local devastation in Japan. (Photo/Shunichi Koshimura)

By Michael Kuhne – AccuWeather

Stretching more than 600 miles (965 km) along the coastline from Vancouver Island down to California’s Cape Mendocino lies a sleeping, tectonic giant capable of causing massive devastation and drastically changing the face of the Pacific Northwest.

The Cascadia subduction zone rests beneath the waves approximately 62 miles (100 km) offshore where the oceanic Juan de Fuca Plate converges and slides under, or subducts beneath, the western edge of the North American continent.

The same fierce geologic forces which gave rise to the Cascade Range and cemented the region’s place in the Ring of Fire have also been responsible for massive earthquakes, volcanism and catastrophic tsunami events in the past.

Continue reading at AccuWeather: Preparing for the Unpredictable: Megaquake, Tsunami May Forever Alter the Pacific Northwest

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By Chris CarringtonThe Daily Sheeple

No injuries have so far been reported after a 5.1 earthquake hit the Northern Californian coast 70 miles west of Ferndale. According to the United States Geological Survey website, the quake struck at 0416 this morning Pacific time.

The largest earthquake to hit California was a 7.9 in 1887. According to the USGS:

This earthquake occurred on the San Andreas fault, which ruptured from near Parkfield (in the Cholame Valley) almost to Wrightwood (a distance of about 300 kilometers); horizontal displacement of as much as 9 meters was observed on the Carrizo Plain. It caused one fatality. A comparison of this shock to the San Francisco earthquake, which occurred on the San Andreas fault on April 18, 1906, shows that the fault break in 1906 was longer but that the maximum and average displacements in 1857 were larger.

California sits in an area that is geologically very active. Plate margins grind against each other causing the tremors. The San Andreas Fault is a huge gash in the landscape that runs from Cape Mendocino down to the Mexican border. It’s a transform or slide fault. The leading edge of the North American Plate and the Pacific Plate slide past each other.

They move in small fits and starts but on occasion get stuck. The pressure builds and builds, until whatever prominence of rock holding them in position gives way, and the plates move causing an earthquake.

Those living on the West Coast know that at some point the ‘big one’ will hit. This could be a quake caused by the San Andreas or one of the other major fault lines such as the Puente Hills fault rupturing, but many scientists think the worst case scenario would be a subduction earthquake caused by the rupture of the Cascadia fault of the coast of California.

The Cascadia Fault is a subduction zone, an area where one of the tectonic plates is forced underneath the plate it collides into.

In the case of Cascadia, the Juan de Fuca Plate is moving under the North American Plate. These plates have been locked together since 1700, 313 years. A particular feature of the Cascadia Fault is that it doesn’t produce small quakes, it remains still and silent until the pressure gets too much and one of the plates slips, giving rise to a mega-thrust earthquake of massive force. These quakes can be compared to the Indonesian quake of 2004 and the Japanese quake of 2011.

The Cascadia fault is long, very long, just over 800 miles (1300km) in length. Based on the findings of the scientists, the tsunami caused by the 1700 event moved inland for more than 60 miles, wiping out everything in its path. Of course in 1700 Seattle wasn’t there, neither was Vancouver, San Francisco, Portland or any of the other cities and metropolitan areas currently occupied by millions of people.

The Cascadia, courtesy of its length, will give rise to a long quake if the whole fault ‘unzips’ at the same time, as it’s believed to have done in 1700. The first P waves will travel the length of the fracture in a minute or two. The S waves that follow, the ones that cause the real damage, are slower and will cause shaking and movement for about five minutes though their speed can vary depending on the rock they are traveling through. (source)

Although there was no tsunami alert issued with this latest quake that won’t be the case if the Cascadia ruptures. Totally silent for 315 years it’s not a case of if the Cascadia will slip but when.

There has been no detected slippage, no detected small quakes. This is a feature of the Cascadia, it is silent until there is a sudden and massive release of energy. There will be no warning whatever. No foreshocks, nothing.

On a dark winters night in January 1700 a tsunami struck Japan. It flooded fields, swept away villages for miles inland and cost many lives. Even as far back as 1700 the Japanese had made the connection between earthquakes and Tsunami, but this time there was no earthquake, no warning to allow the people time to evacuate to higher ground. The tsunami was called the ‘orphan tsunami’ because it had no ‘parent’ earthquake. For more than 300 years the origin of the orphan tsunami remained a mystery.

In 1987 Brian Atwater studied soil samples far inland across the length of the fault and discovered that the United States had also suffered a tsunami at the same time as the Japanese. He concluded that Kanamori and Heaton were correct, a massive earthquake had sent a tsunami out from the source of the quake inundating the coasts on both sides of the Pacific.

Recent studies by researchers at the University of Pennsylvania has concurred on the findings of previous studies. (source)

In any disaster it’s not only the original event that causes problems. The aftermath of a major calamity can cause as many injuries and deaths as the original event. Most of the population are not prepared, they are not able to look after their family in a crisis. Many will sit and wait for the government to ‘rescue’ them, others will be on the prowl looking to supplement their meagre resources by stealing from those who had the foresight to prepare.

At the start of a new year, there is no better time to assess where you are on your preparedness journey. Find the holes in your preps and your plans and plug them while you still have time to do so.

Resources:

The Prepper’s Blueprint: The Step-By-Step Guide To Help You Through Any Disaster

Mr. Heater F215100 MH4B Little Buddy 3800-BTU Indoor-Safe Propane Heater

Information to help you get started prepping

How to Build a 30 Day Food Supply…Fast

The Pantry Primer: How to Build a One Year Food Supply in Three Months

The Prepper’s Cookbook: 300 Recipes to Turn Your Emergency Food into Nutritious, Delicious, Life-Saving Meals

SAS Survival Handbook, Revised Edition: For Any Climate, in Any Situation

The Survival Medicine Handbook: A Guide for When Help is Not on the Way

Elite Large Fully Stocked GI Issue Medic First Aid Kit Bag

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Contributed by Chris Carrington of The Daily Sheeple.

Chris Carrington is a writer, researcher and lecturer with a background in science, technology and environmental studies. Chris is an editor for The Daily Sheeple. Wake the flock up!

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Wiped off the map: Banda Aceh 2004

A report on Fox News this morning talks about ‘The Big One’, the quake that experts know will one day hit California. From Fox:

Jones is heading up a new effort by Los Angeles mayor Eric Garcetti to prepare the city for what experts say is unavoidable: a massive quake similar or worse to the one that hit the city in 1994.

The magnitude 6.7 Northridge earthquake claimed 57 lives and left $20 billion worth of damage in its wake, making it one of the costliest natural disasters in U.S. history. Jones warned the next one will likely have a similar impact.

She estimated the death toll from a quake with a magnitude 7.5 or higher could approach 2,000. That is a figure echoed by California’s Democratic Governor Jerry Brown.

“There’s a better than 50-50 chance that we’ll have a catastrophic earthquake in California that will kill thousands of people and be enormously fiscally devastating,” said Brown in January, when he unveiled his proposal for $1.49 million in funding for a fault mapping project.

He specifically told Los Angeles residents to be cautious.

A study conducted by the Los Angeles Times in 2013 found the city houses more than 1,000  concrete buildings at risk of collapse from a major earthquake because they lack steel reinforcement.

Once gain there is no mention of ‘The Really Big One’. The earthquake that will devastate and make a quake triggered by the San Andreas Fault feel like minor shaking. The Puente Hills Fault has recently been considered as more dangerous to downtown LA than the San Andreas Fault. Both have the ability to cause destruction, but not on a scale where the entire state, or even a good portion of it would suffer damage.

California sits in an area that is geologically very active. Plate margins grind against each other causing the tremors. The San Andreas Fault is a huge gash in the landscape that runs from Cape Mendocino down to the Mexican border. It’s a transform, or slide fault. The leading edge of the North American Plate and the Pacific Plate slide past each other. They move in small fits and starts but on occasion get stuck. The pressure builds and builds, until whatever prominence of rock holding them in position gives way, and the plates move causing an earthquake.

The San Andreas Fault last had a major rupture in 1680. The average lapse between major slips is 150 years, meaning that the pressure has now been building for 334 years.

Other faults branch off the San Andreas Fault and it’s some of these that geologists believe cause the constant minor quakes that Californians live with.

The Cascadia Fault is a different animal altogether.

The Cascadia Fault is a subduction zone, an area where one tectonic plate is being forced down under another. In this case the Juan de Fuca Plate is colliding with, and being forced under the North American Plate.

Running from Northern Vancouver Island to Cape Mendocino California, these plates have been locked together since 1700. There has been no detected slippage, no detected small quakes. This is a feature of the Cascadia, it is silent until there is a sudden and massive release of energy. There will be no warning whatever. No foreshocks, nothing.

On a dark winters night in January 1700 a tsunami struck Japan. It flooded fields, swept away villages for miles inland and cost many lives. Even as far back as 1700 the Japanese had made the connection between earthquakes and Tsunami, but this time there was no earthquake, no warning to allow the people time to evacuate to higher ground. The tsunami was called the ‘orphan tsunami’ because it had no ‘parent’ earthquake. For more than 300 years the origin of the orphan tsunami remained a mystery.

In 1987 Brian Atwater studied soil samples far inland across the length of the fault and discovered that the United States had also suffered a tsunami at the same time as the Japanese. He concluded that Kanamori and Heaton were correct, a massive earthquake had sent a tsunami out from the source of the quake inundating the coasts on both sides of the Pacific.

Recent studies by researchers at the University of Pennsylvania has concurred on the findings of previous studies.

The Cascadia fault is long, very long, just over 800 miles (1300km) in length. Based on the findings of the scientists, the tsunami caused by the 1700 event moved inland for more than 60 miles, wiping out everything in its path. Of course in 1700 Seattle wasn’t there, neither was Vancouver, San Francisco, Portland or any of the other cities and metropolitan areas currently occupied by millions of people.

The Cascadia, courtesy of its length, will give rise to a long quake if the whole fault ‘unzips’ at the same time, as it’s believed to have done in 1700. The first P waves will travel the length of the fracture in a minute or two. The S waves that follow, the ones that cause the real damage, are slower and will cause shaking and movement for about five minutes though their speed can vary depending on the rock they are traveling through.

Any buildings not built to withstand earthquakes will collapse. Depending on the duration and magnitude of the quake it cannot be assumed that even ‘hardened’ buildings will remain standing. Many areas have sedimentary basins under urban sprawl and this amplifies the waves and the damage they cause.

Within approximately 20-30 minutes the tsunami will roll in. Unlike normal waves which have a few yards between them the tsunami waves can have hundreds of miles between them. The entire wall of water displaced when the plates slip hurtles outwards in all directions from the epicenter of the quake. As the waves approach the continental shelf the water at the back of the wave starts to catch up with the water at the front of the wave, which has slowed down as it moves up the incline that marks the start of the continental land mass. Its this that allows the water to build up and give the tsunami its characteristic ‘wall of water’ appearance.

The water will just keep on coming, flowing forward taking almost everything in its path with it. It may or may not be followed by more waves, there is no way to know if it will be a solo wave or a series until it happens. There is also no way to know in advance how deep the water will be. The tsunami caused by an earthquake in Lituya Bay Alaska in 1958 reached 1720 feet.

Lituya Bay is an extreme example, an un-survivable example unless you happen to be Howard G Ulrich or his son. the Indonesia earthquake on boxing day 2004 has been estimated to have had a wave height of between 30-50 feet.

So what do you do with your 20-30 minute warning? Obviously you want to get as high as possible. This is often easier said than done. In a city littered with debris, the dead and dying and glass falling from skyscrapers without warning getting out is going to pose many problems. Highways will be buckled and impassable and there is a great danger from gas main explosions and fires.

Some countries are investing in vertical evacuation centers. High platforms/shelters on stilts that allow the water to pass through the base of the structure without putting extra stresses on masonry that maybe already damaged from the earthquake. FEMA has issued a community guide detailing where such structures will be built / are being built along the West Coast of the United States.

If you don’t have access to a vertical evacuation shelter, or you prefer not to be at the mercy of FEMA,  multi-story parking lots with open sides can offer some possibility of escape. The water is able to flow through the building and out the other side, reducing the chances of collapse due to the weight of the water pressing against it. Be prepared to stay in such a place for a considerable time, help and/or escape is not going to be coming fast. Carry as much food, water and emergency equipment as you can without the weight slowing you down. Think Katrina multiplied by 1000.

It can take anything from a few hours to many days for the floodwaters to subside and even when it does the emergency is far from over. Disease and death with be rife and you should head out of the area as soon as is humanly possible to give yourself the best chance of survival.

Cascadia is locked, loaded and ready to fire. It’s not a case of if, but a case of when. Sadly, with so many variables, an earthquake/tsunami combination is almost impossible to prepare for adequately. The only sure-fire way to survive  is not to be in the area in the first place. (source)

Does the United States Geological Survey think that by keeping quiet it will prevent the Cascadia rupturing? They constantly refer to the San Andreas and it’s associated faults causing major damage in downtown LA or San Francisco, but never seem bothered about the rest of the state.

The damage from a megathrust earthquake of the Cascadia Fault would be enormous, and the loss of life caused by the quake itself and the resulting tsunami would be massive. With so many cities directly in the firing line, the whole state of California would be severely affected.

California grows 85% of the fresh produce consumed in the United States, and any disaster that befalls it will affect the nation as a whole. Can you imagine the United States with 85% less fresh food available? It doesn’t bear thinking about. A rupture of the Cascadia Fault would be a catastrophe of national importance, something that would affect every American to some degree.

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Contributed by Chris Carrington of The Daily Sheeple.

Chris Carrington is a writer, researcher and lecturer with a background in science, technology and environmental studies. Chris is an editor for The Daily Sheeple. Wake the flock up!

 

earthquake

By Chris Carrington

In just 48 hours, South America has been rocked by volcanic explosions and a series of earthquakes.

The news has been full of the 8.2 magnitude quake that struck Chile, but since then they have suffered 27 more quakes of magnitude 5+, three of which were more than 6+ and a 7.6 not long ago at 0553 GMT. On top of this there have been literally dozens of minor quakes.

Panama has had two 6+ quakes some hours apart and numerous smaller shocks. El Salvador, Argentina and Mexico have both experienced 4.2+ tremblors in the last 24 hours and Puerto Rico is currently experiencing smaller quakes of a magnitude between 2 and 3.

Ubina volcano in Peru, quiet for four decades, is throwing up ash which has forced the evacuation of several villages around the base of the mountain.

Ubina is not alone. Reventador in Peru is also erupting as are volcanoes in Mexico (Colima) and Guatemala (Santa Maria, Fuego and Pacaya). Another dozen are showing minor activity and a further 16 are marked as showing signs of unrest. You can see the full list here.

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The jury is out on whether one part of the Ring of Fire can affect another area of a seismically active belt that runs around the Pacific rim and with so much activity south of the Cascadia Fault I hope they are right.

The Cascadia Fault is a subduction zone, an area where one of the tectonic plates is forced underneath the plate it collides into. In the case of Cascadia, the Juan de Fuca Plate is moving under the North American Plate. These plates have been locked together since 1700, 313 years. A particular feature of the Cascadia Fault is that it doesn’t produce small quakes, it remains still and silent until the pressure gets too much and one of the plates slips, giving rise to a mega-thrust earthquake of massive force. These quakes can be compared to the Indonesian quake of 2004 and the Japanese quake of 2011.

The Cascadia fault is long, very long, just over 800 miles (1300km) in length. Based on the findings of the scientists, the tsunami caused by the 1700 event moved inland for more than 60 miles, wiping out everything in its path. Of course in 1700 Seattle wasn’t there, neither was Vancouver, San Francisco, Portland or any of the other cities and metropolitan areas currently occupied by millions of people.

The Cascadia, courtesy of its length, will give rise to a long quake if the whole fault ‘unzips’ at the same time, as it’s believed to have done in 1700. The first P waves will travel the length of the fracture in a minute or two. The S waves that follow, the ones that cause the real damage, are slower and will cause shaking and movement for about five minutes though their speed can vary depending on the rock they are traveling through.

Any buildings not built to withstand earthquakes will collapse. Depending on the duration and magnitude of the quake it cannot be assumed that even ‘hardened’ buildings will remain standing. Many areas have sedimentary basins under urban sprawl and this amplifies the waves and the damage they cause.

Within approximately 20-30 minutes the tsunami will roll in. Unlike normal waves which have a few yards between them the tsunami waves can have hundreds of miles between them. The entire wall of water displaced when the plates slip hurtles outwards in all directions from the epicenter of the quake. As the waves approach the continental shelf the water at the back of the wave starts to catch up with the water at the front of the wave, which has slowed down as it moves up the incline that marks the start of the continental land mass. Its this that allows the water to build up and give the tsunami its characteristic ‘wall of water’ appearance.

The water will just keep on coming, flowing forward taking almost everything in its path with it. It may or may not be followed by more waves, there is no way to know if it will be a solo wave or a series until it happens. There is also no way to know in advance how deep the water will be. The tsunami caused by an earthquake in Lituya Bay Alaska in 1958 reached 1720 feet. (source)

Surviving an earthquake and tsunami is very challenging, but recognizing that should the Cascadia rupture, a tsunami is almost certain to follow gives you a firm footing to plan from. Don’t wait and see. Subduction earthquakes come into the mega-thrust category, and there are rarely, very, very rarely foreshocks. These faults lie silent for decades, sometimes for centuries before they rip. The forces released are unimaginable as it has been building, unreleased since the last time it ripped, in the case of the Cascadia 1700. 313 years worth of tension that will distort and bend the sea bed. The displacement of water in the ocean above the rupture will send a tsunami out in all directions.

You will have 20-30 minutes to get to higher ground. Knowledge about your location, the terrain, and the distance to higher ground will all impact your survival. All the drills in the world won’t help you if you are faced with a 50ft wall of water.

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Contributed by Chris Carrington of The Daily Sheeple.

Chris Carrington is a writer, researcher and lecturer with a background in science, technology and environmental studies. Chris is an editor for The Daily Sheeple. Wake the flock up!