Thursday, August 16, 2007

Shake-N-Quake

Magnitude 7.9 in Peru




This is what a magnitude 6.5 quake looks like on the USGS website from Adak Alaska note the close proximity of the events time wise.
And from that site, it shows a large amount of high magnitude quake activity in August:

# 2007 08 15 - Near the Coast of Central Peru - M 7.9
# 2007 08 15 - Andreanof Islands, Aleutian Islands, Alaska - M 6.5
# 2007 08 14 - Island of Hawaii, Hawaii - M 5.4
# 2007 08 08 - Java, Indonesia - M 7.5
# 2007 08 02 - Andreanof Islands, Aleutian Islands, Alaska - M 6.7
# 2007 08 01 - Vanuatu - M 7.2

We all know that it is just a matter of time before the BIG ONE happens out here on the Left Coast, my guess is real soon, but then I am just a blogger with no scientific background.

What and when, one can only guess. It behooves us all to realize we are mere specs of humanity deposited on an living planet which itself could be called an 'organism' of sorts and as such it changes and evolves daily and earthquakes are part of that continuous evolution.

What will happen if 90% of Los Angeles or San Francisco or any of the many population centers along the West Coast receive a magnitude 7.0 or above(most likely) and are completely leveled with THOUSANDS of dead and millions of injured? Can anyone count on the National Guard? or FEMA? Or will we have to deal with a troupe called Blackwater for rescue and protection against looting and pillaging which WILL happen despite the carnage?

No way to tell what will happen there anymore than we can predict when the actual event will occur.

Expect the best from humanity and the worst humanity has to offer.

One thing for sure, it will change everything.

30 comments:

micki said...

Den -- the lack of preparedness for natural didsasters predates the current state of neglect and incompetence.

I recall a documentary titled "The City That Waits to Die" from the 70s. The film notes the disastrous outcome from building parts of San Francisco on landfill -- the Marina district and much of the hi-rise jungle is built on jell-o. Liquefaction, I believe is the word used throughout the documentary.

The earthquake is inevitable (and some say imminent, whatever that means in geological terms) but there is a scandalous neglect in addressing ways to reduce hazards.

DEN said...

Micki,

Earthquake liquefaction, often referred to simply as liquefaction, is the process by which saturated, non-cohesive soil (sand and silt) loses shear strength during seismic shaking and behaves like a liquid, rather than a solid. The effect on structures and buildings can be devastating, and is a major contributor to urban seismic risk.

Liquefaction occurs when a saturated sand formation is subject to cyclic shaking. The shaking causes increased pore water pressure which reduces the effective stress, and therefore reduces the shear strength of the sand. Soils most prone to liquefaction are loose sands between layers of lower permeability soil that prevent rapid dissipation of cyclic pore pressures. As seen in the figure, uniform sand grains can be packed either in a loose or a compact (dense) formation. Loose sand has usually been deposited gently underwater, either naturally, or sluiced into what is called hydraulic fill. The loose grains can support considerable weight, as they are in contact with each other in a statically stable formation.

Once strong earthquake shaking begins, the grains are separated by high pore water pressure and are no longer resting on each other. Eventually, the grains will settle into a more compact arrangement. However, this transition is not immediate, and requires excess water to leave the formation. For a short period of time, depending how long it takes for the water to drain from the formation, the grains float in a liquid slurry. The excess water is squeezed out which causes the quicksand condition at the surface. If there is a dry soil crust or impermeable cap, the excess water will sometimes come to the surface through cracks in the confining layer, bringing liquefied sand with it, creating sand boils, colloquially called "sand volcanoes".
A liquefaction susceptibility map - excerpt of USGS map for the San Francisco Bay Area. Many areas of concern in this region are also densely urbanized.
A liquefaction susceptibility map - excerpt of USGS map for the San Francisco Bay Area. Many areas of concern in this region are also densely urbanized.

Liquefaction can cause damage to structures in several ways [1]. Buildings whose foundations bear directly on sand which liquefies will experience a sudden loss of support, which will result in drastic and irregular settlement of the building. Liquefaction causes irregular settlements in the area liquefied, which can damage buildings and break underground utility lines where the differential settlements are large. Sand boils can erupt into buildings through utility openings, and may allow water to damage the structure or electrical systems. Soil liquefaction can also cause slope failures. Areas of land reclamation are often prone to liquefaction because many are reclaimed with hydraulic fill, and are often underlain by soft soils which can amplify earthquake shaking. Soil liquefaction was a major factor in the destruction in San Francisco's Marina District during the 1989 Loma Prieta earthquake.

micki said...

Is there a quiz on this? ;-)

DEN said...

We don't need no stinking quizzez!

David B. Benson said...

Den --- Well done.

Micki --- Yes, at the end of the hour.

And, oh yes, my nanoprogress was to take the entire day to squash an obscure bug in a computer program...

David B. Benson said...

Earthquakes:

Magnitude 7.0 and up and called major.

Magnitude 8.0 and up are called great.

There does not appear to be a term for earthquakes of magnitude 9.0 and up, only three such in the last 100 years. I suggest stupendous.

Or did I say all that already?

DEN said...

DJIA is Down 297 points at this hour.

Another Black Friday?

DEN said...

Earth isn't the only thing shaking right now.

Doc, Stupendous sounds good to me, hope that never happens.

Alan said...

Welp, so far it looks like I've 'weathered' the storm. Water didn't get in my house or anything, but the bridge to my mailbox over the city easement used for drainage is underwater. Clear Creek is just down the street, where it all drains into, but it backs up some at my corner house because it drains a newer neighborhood across the street, plus the water comes down my side street and makes a right turn at my house to go to the creek... kind of a double whammy. My yard looked like a lake, but it was quite a ways from coming inside the house. It's drained down quite a bit now. "whewww"

David B. Benson said...

The Lisbon earthquake of 1755 was perhaps magnitude 9.0. Anyway the effects were certainly stupendous.

But otherwise I know of only the earthquakes in Southeast Asia, Alaska, and the west coast of South America in historical times being stupendous.

Alan --- I'm glad your feet are still dry. But do note that global warming means ever intensified storms...

Alan said...

Alan --- I'm glad your feet are still dry. But do note that global warming means ever intensified storms...

Yeah, I hear ya Dr. B. Tropical storms, depressions, and out-and-out hurricanes are standard fare 'round here, so this one wasn't that big of a deal. But...
*fingers crossed*

º¿carol said...

Fall is in the air. Everyone HATES when I say that. I noticed very few birds singing at dawn now like they were a couple weeks ago. Then it was a cacophony of songs.

Oh, well. I'm sure we won't need to turn the new furnace on for quite some time yet.

Off to read the Lansing paper. Bob just yelled to me that they are going to put cameras around Lansing to try to stop crime. Oh, BOY are the posters going to be mad! We just got thru arguing about that. There was a 76 year old woman, mother of a councilwoman, neighborhood activist and snitch on the druggies on her block that got beat to death in her home. That's when the idiots that run Lansing decided they needed cameras around town. Hello!!!! SHE WOULD STILL HAVE BEEN BEATEN TO DEATH IN HER HOME!!!

Gerald said...

An earthquake may be the 9/11 wish

Gerald said...

If the Bush administration treated the 9/11 attacks for what they were — a crime, rather than an act of war — and committed the nation's resources to tracking and apprehending the masterminds of the crime, President Bush would be a hero right now.

But the decision was made to use 9/11 to not only invade Iraq, but ram through all sorts of measures that made mincemeat of our Constitution. From the Patriot Act to Guantanamo Bay to illegal spying on Americans to the suspension of habeas corpus, 9/11 has become the justification for some of the worst infringements on our civil liberties in our nation's history.

Gerald said...

Terrorist Nation

Gerald said...

The idea that the US could be considering classifying the Iranian Revolutionary Guard as a “terrorist” organization, based upon some dubious evidence that the organization is supplying some weapons—in particular those shaped charges that have been so effective in roadside bombs against US military vehicles—is pretty preposterous when you consider the source.

Whatever the truth about the activities of the Iranians, certainly when it comes to terror, the US is unrivalled in the world today.

By the latest estimate, over one million people have died in Iraq because of the American invasion of that country, and despite a virtual media blackout over that entire country, and the self-censorship practiced by the US media regarding Iraq, more and more evidence keeps trickling out that the vast majority of those deaths have been caused, directly or indirectly, by the American forces. While we read in lurid detail about every bomb blast detonated by Shia and Sunni fighters that hit Iraqis or that kill or wound Americans, we hear barely a word about the killing of Iraqi civilians by US forces, and it’s clear that adding up all of those publicized Iraqi-on-Iraqi attacks you don’t come close to a million dead. Guess who’s killing the rest?

Gerald said...

Guess what president has been granted to use nuclear weapons in a conventional war

Gerald said...

I am fifty-eight
now, and believe that God's compassionate vision
requires our partnership. Sorry, God, we haven't been
doing too well: that childish maniac of a President
seems as delusional as the screaming schizophrenics
who make book-shopping an ordeal on Telegraph Avenue.
I don't begrudge those wounded, smelly souls a thing;
I want them to have what they need. I don't even
begrudge President Bush his wealth, security or his
ranch; if he would go back to Texas and realize his
original dream of becoming Baseball Commissioner, I
wouldn't think about him.

Gerald said...

The Elite Few

Gerald said...

My philosopy is this:

You are on this earth for a reason - to fight for the light. Your words are swords that penetrate the darkness with truth and light. You have a purpose.

To this end, I submit my thoughts and observations. I welcome the same from you.

Gerald said...

A Nazi general says we should consider the military draft. Of course he is pro-draft. Without cannon fodder and wars he would be out of a job.

NO NORMAL PERSON WILL CHOOSE WAR OVER PEACE!!!!!!!!!!

DEN said...

Gerald, These are NOT normal human beings, rather they are ruthless killers in positions of high political authority that we cannot get rid of.

BOHICA

º¿carol said...


THE ARCHITECTS OF WAR: WHERE ARE THEY NOW?

David B. Benson said...

Besides earthquake magnitude, it appears there are sometimes super-speed effects: it takes a long, straight fault.

Like parts of the San Andreas?

micki said...

Whew! I ducked out on the quiz.

Dr. B, I'm very happy for you that you made nanoprogress on your computer bug problem, but I had hoped the progress you mentioned was related to mitigating climate change, MmmmmmPeachMint, or ending bush's War of Choice -- or ALL three!

But, alas, no progress to speak of on any of those counts...

micki said...

The Next Big One: Where on Earth Will It Strike?

From National Geographic....

David B. Benson said...

I squashed another bug today.

No progress on those other three matters, at least by me...

DEN said...

Squashed Bugs

micki said...

I heard Tony Snow is resigning.

In his case, it probably is about spending more time with his family. He's in pretty bad health.

DEN said...

USGS EARTHQUAKE STE ABOVE IS INCORRECT!! This is correct:
http://earthquake.usgs.gov/data/