Posts Tagged ‘Earthquake’

It’s been nearly two weeks again!  Yikes!  But I’ve got another excuse.  Here goes…

The back trouble I’ve been fighting has taken a more serious turn.  Last week, the pain just wouldn’t go away, even with a couple trips to the chiropractor, who usually fixes me right up.  So we went to clinic and got some stronger medicine, which helped my back a lot.  The next day, I felt much better…until I got into the shower.  After three or four minutes, I could hardly stand up.  I grimaced through and dragged myself back to bed.  An MRI on Friday revealed the bad news:  a badly herniated disk in my lower back is pinching a nerve that runs down my leg.

It’s most uncomfortable except when I’m laying on my right side in bed with my legs curled up…which is where I’ve spent about 90% of my time since last Tuesday.  We meet with an orthopedic surgeon tomorrow morning, and surgery is almost certain.  But if it will get things fixed so I can work from the office (instead of curled up – any idea of how hard it is to type?!?) and get back on my bike again, then I’m okay with it.

Well, it’s either that or “the dog ate my homework.”

When someone mentions “disasters” and “1985” in the same sentence, my mind’s eye immediately sees those barfalicious parachute pants, break-dancing, and those glasses girls wore that looked like they were upside down.  It doesn’t get a lot worse than that.  But those are fashion disasters.  And though the carnage from them was great, I suppose it pales in comparison to a real disaster.

A disaster like, say, the one that hit Mexico City on this day.

The sun had just come up over Mexico’s capital on September 19, 1985, when the calm was replaced by a violent shaking.  Some 220 miles offshore, a strong 8.0 earthquake had rattled itself into existence.  Now your mind immediately jump to the giant quake that hit Japan in March of last year.  That earthquake did very little damage.  The massive tsunami that followed shortly after, however, was a completely different story.  But tsunamis were not the issue in Mexico City.

So now you might think that, due to the distance from the quake (actually quakes, as this particular temblor was a two-headed beast), Mexico might avoid serious trouble.  But, unfortunately, that was also not the case.

The earthquake occurred in an area that’s known for stronger seismic activity, as there are a couple of tectonic plates that conflict with each other.  I have an earthquake app on my smartphone, and this region sees small-to-moderate quakes pretty regularly.  But in 1985, it had been a while since there was a “relieving of the pressure” in this particular place, so the pent-up stresses were released all at once rather than gradually over a series of smaller quakes.

But the real culprit was Mexico City itself, or rather, it’s location.  The city, one of the world’s largest, sits in the Valley of Mexico.  Hundreds of years ago, the area was a large lake.  The Aztecs built their capital (then called Tenochtitlan) on an island in the middle of Lake Texcoco.  Over time, the city grew.  Then there was a change of ownership when the Spanish came calling, but still the city grew.  It outgrew the island, so over time, the lake was drained for more infrastructure.

I’m no geologist, but I would guess that lake beds don’t make good foundations, because while it may be dry on top, there’s likely still a lot of moisture underneath.  The soils below Mexico City were volcanic clay…with a high water content.  When the shock waves from the quake hit, those soils actually made the shaking worse.  And of course, those soils also settle, which causes buildings on top of them to become very unstable.   That’s what happened in Mexico City.

Hundreds of buildings completely collapsed and thousands more were heavily damaged.  In addition, the shifting landscape tore up roads and wreaked havoc on underground water, sewer, and gas lines.  Sections of the city were completely devastated.  The number of deaths varies widely depending on the source, but ranges run from 10,000 to more than four times that number.

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The San Francisco earthquake needs no real introduction.  And that’s true despite the fact that the city surrounding San Francisco Bay is bumped and jostled by a good many quakes each year.  Most of them are rather mild and I suppose some that can be detected by seismic equipment aren’t even felt by the public.

But many can be felt, even if only a little.  Living in the Midwest, I’ve never experienced an earthquake, so I have no idea what one feels like.  I imagine there’s a low rumble and then some wiggling around for a few seconds.  Maybe one feels a bit woozy and disoriented, sort of like air- or sea-sickness, but again, I’m just guessing.  Californians have a far greater depth of experience than I.

Like I said, most quakes are fairly small, but there have been some biggies.  There was a powerful quake that struck in 1989 as the World Series was getting underway…we’ve talked about that one.  But when someone mentions The San Francisco Earthquake, just one is being referenced.

The earthquake that struck on April 18, 1906.

Residents of the city were jolted awake shortly after 5:00am by a powerful shock that measured 7.9 on the Richter Scale, as the San Andreas Fault (which runs just west of the city and bay) ruptured along 300 of its 800 miles.  I’m not an expert, but from what I’ve read, the San Andreas Fault is where two of the earth’s plates meet.  The western plate tends to edge north while the eastern place moves south.  Over time, stresses build up as the plates grind against each other.  Then the pressure releases in a quake.  Most are small, but this particular one was not.

It toppled buildings and homes on a grand scale, causing tremendous damage.  But just as devastating was the resultant fire which, combined with the quake, destroyed upwards of 80% of the city.  Most of the pictures of the quake’s aftermath show destruction on par with cities that were heavily bombed during the Second World War.  More than 3,000 lives were lost and more than half the city’s population was left homeles, making it California’s worst natural disaster, and one of the worst disasters in U.S. history.

Today, structures on the West Coast are built with the various fault lines in mind.  Much like Japan, everything is done with “an eye toward the ground.”  In every sense, San Francisco is far more prepared to deal with earthquakes than, say, St. Louis, which also sits in relative proximity to a fault.  But as I said before, the San Andreas still lurks…

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The other night we watched yet another of those “disasters of the Apocalypse” shows that seem to pop up with almost absurd frequency these days.  It’s usually the Discovery Channel, or the History Channel, or the Learning Channel, but they’re on all the time.  I suppose it has something to do with the ominous approach of 2012, the year the Mayan calendar ends and a bunch of people believe “the big one” is going to go up.

Didn’t the Mayans live a thousand years ago?  Their calendar probably ended in 2012 simply because they found more entertaining ways to occupy their time.  Hopefully the weight that lots of people give to this nonsense is mostly just a figment of my imagination, because if it’s not, then there are a lot of people that haven’t (unlike the Mayans) found more entertaining ways to occupy their time.

But I digress.  Anyways, this show was one we hadn’t seen before and was narrated by Samuel Jackson.  It was sort of a countdown of the various ways lots of people could get killed by disasters.  There was a big rainstorm over California at Number 5.  Number 4 I can’t remember, but I’m sure it was worse than a container of duck toys spilling into the Pacific.  Numbers 2 and 1 were completely predictable.  Two was a massive tsunami caused by a volcanic eruption and landslide at La Palma island in the Azores…this has been described on a dozen different “what-if” shows.  And of course, Numero Uno was the mega-volcano erupting in Yellowstone, which would lay waste to most of the American existance.  Again, we are not surprised, as this potential disaster is also well-known.

It was Number 3 that most caught my attention…an earthquake.  To be more specific, an earthquake in the Midwest.  Earthquakes in this area aren’t nearly as famous as those occurring around the Pacific Rim and the corresponding Ring of Fire, because they’re so rare.  But when the bigger ones hit, they pack a powerful wallop.

The most famous of the “Midwest” quakes on record was a series of temblors that culminated in a tremendous quake in February of 1812.  Centered over southeast Missouri, northeast Arkansas, and western Tennessee, the biggest ones were felt over a 1,000,000 square miles and damage was recorded as far away as Maine.

But it all began 200 years ago today…December 16, 1811.

At 2:15 in the morning, people along the New Madrid Fault were thrown from their beds by a tremendous rumbling.  They scrambled out of their crumbling homes and got a night-time view of the apocalypse, as the landscape heaved and bucked like a drunken man, under the influence of a quake that would have registered close to 8.0 on the Richter Scale.  There were sand blows and landslides, soil liquifaction and, to hear the locals tell it, a brief reversal of the mighty Mississippi River.

Six hours later, another quake similar in scope struck the region again.  Too large to be an aftershock, it classifies as its own separate quake.  People all over the region were terrified, looking heaven-ward and awaiting the arrival of the Four Horsemen.  Damage was extensive, but deaths relatively light because the population was sparse.

For many years, scientists believed that major earthquakes struck along the New Madrid Fault every couple of hundred years.  And guess what?…we’re at exactly 200 years today.  But seismic activity along the fault has dwindled to a relative handful of very small shakers each year.  I read somewhere that geologists think the fault might be seizing up to a point where quakes no longer occur.

But for the millions of residents that live in St. Louis, Kansas City, Memphis, Chicago, and other large cities in the region, there is that small concern.  I live in central Iowa, several hundred miles from the fault, but I think about it all the time.  Homes in the Midwest are built with tornadoes (and in recent years, flooding) in mind, not earthquakes.

A repeat of the quakes that began two centuries ago would be cataclysmic.

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Several months back I got a smartphone.  I really didn’t have much interest in one at the time, but since our company was planning to build a mobile version of one of our websites, it kind of made sense (as one of the developers) to have one.  So now we’re developing the site, and it’s been pretty handy.  In the meantime, I’ve added a few free apps to the phone, which have made the fact that it’s bulkier than its predecessor a little more bearable.  One of the first apps I installed was one called “Latest Quakes” that allows me see when quakes occur anywhere in the world.  And this year, we’ve had plenty of them to view.

Back in 1755, smartphones didn’t exist.  Dumb phones didn’t exist, either.  But earthquakes did, and they could certainly be felt, whether seismographs were around or not.  And one of the largest quakes to hit the eastern seaboard occurred on November 18, 1755.  The quake has been estimated to be something greater than 6.0.  Now that doesn’t sound especially large in light of the quake that struck off Japan’s coast back in March, but apparently, the composition of the ground east of the Rockies means that earthquakes have a greater “punch per Richter number”.

This particular quake struck early in the morning off the coast of Massachusetts.  It was in the general vicinity of Cape Ann, so it’s been named the Cape Ann Earthquake, but the shaking wasn’t limited to Cape Ann.  It was felt as far south as South Carolina and well out into the Atlantic.  Damage in eastern Massachusetts was pretty extensive.  Since the Richter Scale didn’t exist back then, earthquakes were measured by the Chimneys-Knocked-Down Scale.  Jay Feldman quotes the Boston Weekly News-Letter in When the Mississippi Ran Backwards (which, by the way, is a completely fascinating read)  “The Convulsions were so extreme as to wreck the Houses in this Town to such a Degree that the Tops of many Chimnies…were thrown down…”.  Fences were reported knocked down and there was some soil liquifaction as well.

Many citizens pointed ominously to the sky and fingered the Hand of God as the cause of the quake, citing punishment for evil deeds and immoral behavior.  This led to something of a religious revival, as preachers took the opportunity to remind their congregations of the Almighty’s Powerful right hand.  It also led to a lot of employment opportunities for guys that knew something about brickwork.

Recommended Reading: When the Mississippi Ran Backwards: Empire, Intrigue, Murder, and the New Madrid Earthquakes – A super-intriguing tale. A little murder. A little earthquake. A Cape Ann mention.  I think you’ll like it.

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The earthquake that rocked Alaska on March 27, 1964 needs no special introduction.  It is the most powerful earthquake recorded in the Northern Hemisphere.  Only two others, the great Chilean earthquake of 1960 and the 2004 quake off Sumatra (which caused that terrible tsunami), have approached or surpassed the Alaskan quake’s strength, which struck in the Prince William Sound area shortly after 5:30pm on Good Friday.

Geologists believe that earthquakes occuring along subduction zones tend to be more powerful than quakes along standard fault lines, because greater stresses build up as the upper plate passes over the lower.  The Alaskan quake was of that type and, while I wasn’t alive when it happened, the pictures show tremendous damage.

The land buckled and heaved during the 4-minute quake, permanently rising as much as 30′ (the Kodiak area) in places while dropping 10′ in others, creating new beachlines and opening fissures in the surface.  In the photo above, you can see how the beach areas of Middleton Island on the left slid nearly 12′ from its original level on the right.

Of course, the forces we are discussing here were astronomically stronger than any man-made structures.  Anchorage was heavily damaged, as were a good number of smaller cities and towns.  In fact, significant damage was reported over an area covering more than 50,000 square miles from a quake that was felt over more than half-a-million square miles.  Thousands of major aftershocks over the next 18 months served to terrorize an already stunned populace trying to put their lives, homes, and infrastructure back together.  But its effects were even more far-reaching.

The rapid shift along the plates triggered tsunamis that were detected throughout the Pacific Ocean and caused widespread damage.  While deaths from the quake itself (falling buildings, etc.) were incredibly few (10-15, depending on your source), 120 fatalities were caused by tsunamis.  Crescent City, on California’s northern coast, was particularly hard hit, where 14-foot waves were responsible for 11 deaths and millions of dollars of damage.

But the location of the Alaskan earthquake (well off the equator in the upper Northern Hemisphere) also caused the planet to wiggle, which means that the effects of the quake were seen worldwide.  Small tsumani waves were detected in Cuba, small boats were reportedly capsized off Louisiana’s coasts, and water oscillations were seen in Africa.

Here in the central United States, we occasionally mention the fabled “big one” that supposedly will someday strike the San Andreas Fault and knock the most heavily-populated parts of California into the Pacific, while simultaneously casting a wary glance in the direction of the New Madrid Fault, knowing we stand on shaky ground ourselves.  But I think a good number of us would like to believe that “the big one” has already come and gone, striking the Alaskan coast 46 years ago (as of this writing).

Time will tell if that belief stands up to the motion of the tectonic plates.

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It was only a couple of weeks ago that a massive earthquake struck just off the coast of Chile.  The early morning quake lasted an astounding 4 minutes and weighed in at an astonishing 8.8 on the Richter Scale.  Within a very short time, tsunami warnings were being posted all over the  Pacific Ocean.  Around noon the focus (at least for the U.S.) narrowed to the Hawaiian Islands, where the waves, which travel at high subsonic speeds, were scheduled to strike.  Estimates suggested waves of 8′, which would probably have done some significant damage.

My folks had come to visit for the weekend, and we turned on the TV to see what happened.  When nothing much came of it, the news reporters started fumbling around a bit, and for us it turned into a bit of comical farce.  Of course, some places along the Chilean coast were heavily damaged by tsunamis, but most of the Pacific (including Hawaii) was spared.

But that was not the case on March 9, 1957.  On that date, a huge earthquake struck the Andreanof Islands (on the southwest part of the Aleutian Islands) near Alaska.  Tsunami waves in the immediate area approached 70 feet, but as expected, those waves spread out through the Pacific Ocean and struck Hawaii.  And they were not the small “2010-style” waves.

Maximum wave heights were nearly 50′ on Kauai, more than 20′ on Oahu (from where the picture above was taken), 15′ on Molokai, and more than 10′ on Hawaii itself.  Damage was immense as hundreds of homes were destroyed, bridges and highways were washed out, and floodwaters washed through businesses and homes.

But miraculously, not a single Hawaiian (or visitor to the islands) was killed, though the damage was extensive, topping $5 million.

We’re familiar with flooding from dam breaks (and we talked about a couple of those, here and here, and the schedule calls for another in a couple days).  And even I know the terrible power of river- and stream-flooding first-hand (and it’s threatening us again as I write this).  But tsunamis are in a class all their own.  The volumes of water, the speed with which they strike, the total destruction and widespread death and calamity they can bring are on a scale most of us can’t grasp.

Well, in the aftermath of the 2004 Indian Ocean tsunami which many of us have seen on video, maybe we can to a degree…and it’s very sobering.

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When the words “Lituya Bay” are mentioned (which, to be perfectly honest, doesn’t happen all that often), I think of those Old Milwaukee beer commercials from years past.  You remember the ones?  They go something like…

Lituya Bay and Milwaukee both mean something great to these guys.  Lituya Bay means Alaska, America’s wildest frontier.  Beauty, wildlife, fishing.  And Milwaukee means beer…cold, crisp, Old Milwaukee beer…

You get the idea…and yeah,  it’s pretty stupid.

In case you didn’t know, Lituya Bay is a small natural fjord (2 miles wide by 7 miles long) along the southeast coast of Alaska…right about here.  It serves mostly as a shelter and anchoring point for small fishing boats, but its relatively dramatic tides and high current speeds at the entrance give mariners some extra action when navigating.

Typically a quiet little harbor, Lituya Bay was never in an Old Milwaukee beer commercial.  But it was the sight of one of the most dramatic events in recorded geological history.  On the evening of July 9, 1958, a magnitude 7.7 earthquake shook the Fairweather Fault, which crosses our little harbor.  Earthquakes are not uncommon, but the results of this quake certainly were.

At the back of the harbor, 40 million cubic yards of mountain broke free and collapsed into the water, creating a huge tsunami.  As the water ripped through Lituya Bay, it spread out and got smaller, but its initial height is still the highest ever seen…516 meters.  That’s 1,720 feet high…a third of a mile.  For comparison, the World Trade Center’s North Tower (including antennas) stood 1,728 feet tall.  That’s a colossal wave!

Anyways, near the mouth of the Bay sat Howard Ulrich and his 7-year-old in their small fishing boat.  Having anchored just a couple hours before, they got the shock of their lives when the earthquake struck.  Two minutes later they got a second (and bigger) shock in the sound of a deafening crash and what looked to be a massive explosion at the head of the harbor.  Three minutes after that, the wave, still nearly 100 feet high, hit their boat, carried them out over the shore, then backwashed them into the middle of the harbor.  Miraculously, both survived.

The Lituya Bay tsunami stripped away the trees, vegetation, and even the dirt in its path, leaving bare rock in its wake.  Fifty years later, the effects of the landslide can still be seen in Lituya Bay, a stark reminder to the incredible power of water.

Recommended Reading: Geology.com website – This site has a great amount of detail and great photos of the Lituya Bay tsunami.

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When we think of earthquakes, we tend to think of specific places like San Francisco or Alaska, where major quakes have occurred.  We probably also think of places like Indonesia and Bande Aceh, where an underwater earthquake and subsequent landslide caused the immense tsunami on December 26, 2004.  Others of us may think in more general terms, like the Ring of Fire, the large volcanic and seismic zone ringing the Pacific Ocean that has spawned much of the activity in the places I just mentioned.

But rarely do we think of the central United States when discussing topics related to seismology.  And that’s easily understandable, because earthquakes in Mississippi River Valley just don’t happen all that often.  But when they do,…

It’s a relatively unknown geological fact that, as the longest river in the United States flows past southern Missouri, Tennessee, and Arkansas, it passes over a sizeable fault line.  Known as the New Madrid Seismic Zone, it encompasses the aforementioned states (as they border on the Mississippi River) as well as southern Illinois, western Kentucky, and even the northern tip of Mississippi.  And in this area there have thousands of minor temblors and quakes in recent years, though no major quakes.

For those, we need to go back to the winter of 1811-12, when major quakes were recorded, quakes that rank as some of the most powerful in U.S. history.  Beginning in December of 1811, two major quakes were followed by numerous smaller shakes and aftershocks.  But all of those were the lead-up to the biggest of the quakes, which rocked the Midwest on February 7, 1812.  Centered around New Madrid, Missouri, estimates have the quake at 8.0 on the Richter Scale, and it was felt on a massive scale.

How massive?  Stories are told that the quake cracked sidewalks in the nation’s capital and knocked down chimneys in…are you ready?…Maine.  All told, the quake was felt in an area that covers 1,000,000 square miles.  By comparison, the infamous 1906 San Francisco Earthquake covered only about 6,000 square miles.  Though the scale was partially due to the bedrock in which the quake occurred, this was still a tremendously powerful quake.

Today, the fault is still active, and there is growing concern that another major shake-up is building, particularly since we are now approaching 200 years since the quakes of 1812.  What’s more, there has been very little earthquake preparation in the Midwest, and nothing at all approaching the scale of more earthquake-prone areas.  A repeat of the 1812 events would be catastrophic, considering the major population centers that could be affected.

Recommended Reading: When the Mississippi Ran Backwards: Empire, Intrigue, Murder, and the New Madrid Earthquakes – History, intrigue, and mayhem in one volume.  I’ve yet to read this book, but from what I’ve seen, it’s going to be part of my next book order.

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Let’s see…what would I have been doing at about 7pm on October 17, 1989?  If memory serves me right (and it doesn’t), I was probably sitting at home relaxing after yet another day of exposure to college life.  Baseball’s World Series was going on at the time, but since it was Oakland and San Francisco and not the Atlanta Braves (who had endured another horrible season), I wasn’t really interested.

At the same time in San Francisco, people may have been heading home early or driving to Candlestick Park for the big game.  Many would have been working in their offices or taking an afternoon nap.  Regardless, the lives of Bay-area residents were about to be turned upside down…in the most literal sense.

Just a couple minutes past 5pm, a monster earthquake, measuring 6.9 on the Richter Scale, struck the Bay area, caused by a large slip along the infamous San Andreas Fault.  According to experts, the earthquake only lasted about 15 seconds or so, but the energy released in the slippage was equivalent to exploding (and this is hard to fathom) nearly 54 billion pounds of TNT.  That’s more than 1,000 times larger than the atomic bomb that was dropped on Nagasaki.  That’s a lot of power and, needless to say, the results were catastrophic.

While damage was concentrated in San Francisco, it certainly wasn’t limited to just that area, as heavy damage was reported in locations nearly 60 miles from the epicenter.  The quake was felt as far east as Reno, NV and as far south as Ventura, CA.  Thousands and thousands of buildings and homes collapsed, numerous sections of the Interstates split apart, as did hundred of highways and city streets.  Many bridges were heavily damaged, with some collapsing altogether.  Ruptured gas lines caused numerous fires.  Total damage would run into the billions of dollars.  Even the Goodyear Blimp, flying above Candlestick Park, was bounced around by the quake.

Sixty-three people lost their lives as a result of that 15 seconds in October, two-thirds of them on the collapsed Cypress Street Viaduct in Oakland.  More than 3,700 people were injured, and hundreds of thousands of lives were changed forever, as upheaval, uncertainty, and helplessness became the order of the days and months ahead.

Almost 20 years later, the homes have been rebuilt, buidings have been reconstructued, and the roads and bridges are servicing traffic again.  But the San Andreas still lurks…

Recommended Reading: The Loma Pietra Earthquake – The U.S. Geological Survey site.

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