Category: earthquake

Newspaper Clippings from the 1964 Alaska Earthquake at Gwennie’s

The Anchorage Daily Times with a front-page report on the 1964 Alaska Earthquake.

I’d like to write a few more posts about my visit to Alaska earlier this year. In case you missed them, here are some earlier posts about Alaska:

Off to Alaska…

Geology Word of the Week: G is for Glacial Erratic

Iditarod Start and Finish

A Drive to Salmon Lake, Alaska in Pictures

Nome, Alaska in Pictures: Part I

Nome, Alaska in Pictures: Part II

Nome, Alaska in Pictures: Part III

Monday Geology Picture(s): Garnet Sands in Nome, Alaska

Bering Sea Sunset

Muskoxen Near Nome, Alaska

Plane Views: Anchorage to Nome

Plane Views: Minneapolis to Anchorage

Sledge Island Scenery

And, last but not least…

Whale Carcass on the Beach in Nome, Alaska

Clearly, I’ve already shared a fair amount about the two months I spent in Alaska. However, I still have some more to share! I’ll start out with a post about Anchorage and a very big earthquake.

My husband Jackie and I spent a few days in Anchorage back in July before traveling up to Nome, where we spent the months of August and September doing field work. One day when we were in Anchorage we had lunch at a place called Gwennie’s Old Alaska Restaurant, a place that had been recommended to us by some locals.

Outside of Gwennie's Restaurant.

Gwennie’s is full of kitsch and crazy: taxidermied animals and antlers are strewn about everywhere, and in-between one finds everything from Iditarod posters to stained glass windows depicting gold prospectors. The food is served on cheap plates with cheap cutlery, but it’s pretty good. Both my husband and I enjoyed the reindeer sausage with fries and a large drink since we were dehydrated from running errands all over Anchorage on a beautiful, sunny, warm summer day.

Gold panning themed stained glass.
Jackie and his bear friend.
Wishing pool and more taxidermy.
A bear rug... attacking from above!
Restaurant decorations: antlers, a saw, a sewing machine, and a piano.
Posing next to a muskox head.
Iditarod posters.

Jackie and I enjoyed looking at all of Gwennie’s unusual decorations, most of which had an Alaskan theme. As we were wandering around looking at the various decorations, one of the waitresses suggested that we go over to the bar to take a look at all of the newspaper clippings from the 1964 Alaska earthquake. This earthquake was enormous, registering 9.2 on the Richter Scale. For reference, that’s the same magnitude as the 2004 Indian Ocean earthquake that created the large tsunami that devastated parts of Asia. Jackie and I had heard and read about the 1964 Alaska earthquake before, but seeing the newspaper clippings and pictures really put the earthquake in perspective. The clippings put a human face on the earthquake, which was so destructive that some Alaskan towns never bothered to rebuild but simply were abandoned. Looking at the pictures of the earthquake’s destruction was fascinating, humbling, and awe-inspiring.

Here are some of the earthquake newspaper clippings that we saw at Gwennie’s:

1964 Alsaka earthquake newspaper clippings on the wall of Gwennie's bar.
Another view of some newspaper clippings on the bar wall.
A closer view of a newspaper front page.
Pictures of earthquake destruction in downtown Anchorage.
More pictures of earthquake destruction.
Yet more pictures of earthquake destruction.
More earthquake newspaper clippings on another wall of the bar.
A closer view of more earthquake newspaper clippings.
Even more destruction.

If you’re ever in Anchorage, I highly recommend going to Gwennie’s for a bite to eat and a look around. At least have a drink and take a look at the earthquake newspaper clippings.

Why are there Earthquakes and Volcanoes in Japan? In Response to: Magnitude 8.9 Earthquake & Tsunami in Japan

For those of you who have not yet heard, there has recently been an enormous Magnitude 8.9 earthquake and an accompanying tsunami in Japan. There are currently tsunami warnings for the Pacific, so if you live on the West coast of the US or anywhere in the Pacific Ocean, please be cautious. The USGS (US Geological Survey) tsunami warning for the US can be found here.

Below is a map of estimated tsunami travel times. CNN has converted these to Pacific Standard Time estimates.

Estimated tsunami travel times. Figure taken from NOAA here. Click to view larger. Note there is an error in this figure: the star is in the wrong place. The earthquake actually occurred farther north, where the waves originate.

My fellow geobloggers are currently doing a great job of covering the recent news of the Japan earthquake. Callan Bentley over at Mountain Beltway has a good summary of earthquake coverage.

Here are a few more geoblogs & websites discussing the Japanese earthquake. I’ll update this list as I find more good sites:

Geoblogs:
Mountain Beltway
Dan’s Wild Science Journal
Paleoseismicity
Geotripper
Highly Allochthonous

Other Websites:
USGS
NOAA’s West Coast and Alaska Tsunami Warning Center
NOAA’s Pacific Tsunami Warning Center

Since I have quite a few non-geologist readers, I thought I would quickly discuss why Japan is such an earthshaking place with so many earthquakes, tsunamis, and volcanoes. While the gigantic 8.9 magnitude earthquake is impressive even for Japan, this is a part of the planet where geologists expect large and frequent earthquakes. Historically, there has been quite a bit of earthshaking in the area of Japan where the recent, enormous earthquake originated.

Here are a few historical maps from the USGS showing seismicity (aka earthshaking) in the area where the recent Japan earthquake originated. The location of the recent earthquake is given as an orange star:

 

Figure taken from USGS here. Click to view larger.

 

 

Figure taken from USGS here. Click to view larger.

The first figure shows that there have been many large (greater than magnitude 7)  and shallow (meaning more destructive at Earth’s surface) earthquakes in this area of Japan since 1900. The second figure shows that there has been quite a bit of earthshaking- both small and large- in this area of Japan since 1990.

Why is there so much earthshaking in Japan? Simply put, there is so much earthshaking in Japan because the Japanese islands are part of a volcanic island arc.  As a quick reminder for those of you who are a little rusty on Geology 101, a volcanic island arc is a place where volcanoes are produced above a subduction zone. A subduction zone is a place where one tectonic plate is going underneath (aka subducting) another tectonic plate.

Here are a couple of images showing subduction:

Volcanic island arc & subduction zone. Figure taken from here. Click to view larger.
Artistic (not quite scientifically accurate but very pretty) depiction of an island arc & subduction zone. Image taken from here. Click to view larger.

When an oceanic plate subducts underneath a continental plate, this produces volcanism on the continent, such as the volcanism that occurs in the Western US in the Cascades. When an oceanic plate subducts underneath another oceanic plate, a volcanic island arc is formed. There is no land originally, but a chain of island arcs builds up as volcanism develops above the subduction zone.

Here is a figure showing that Japan is part of a greater subduction zone called the Pacific “Ring of Fire”:

Plate boundaries, subduction zones, and volcanoes in the Pacific “Ring of Fire.” Figure taken from here. Click to view larger.

But why is there volcanism above a subduction zone? Well, this relates to a fundamental concept in geology- why do rocks melt?

A common misconception is that rocks melt because they are heated. Actually, most of the time rocks do not melt because they become hotter. Think about it- the interior of the Earth is very hot, much hotter than the shallow Earth where melts feeding volcanoes are generated. Yet, the interior of the Earth is pretty much all solid, except for the outer core. The reason that the interior of the Earth is not all melted, even though it is very hot, is because there is also an enormous amount of pressure in the interior of the Earth. So, when thinking about whether or not a rock will become molten, you need to think about both temperature and pressure.

Most rocks on Earth actually melt because of a sudden change in pressure. Geologists often talk about fancy shmancy “adiabatic decompression melting” occurring at mid-ocean ridges. To translate this into everyday language, “adiabatic decompression melting” just means that melting occurs because rock is moved quickly upward in the Earth. Rocks tend to lose heat very slowly, so if they are brought upwards quickly enough they won’t have time to cool down. They remain hot, but because they are brought up to a more shallow part of the Earth, they have less confining pressure and are able to melt. To breakdown the previous phrase: adiabatic = no heat loss, decompression = less pressure, and melting = solid to liquid.

So, at mid-ocean ridges- places where tectonic plates move apart and rocks are able to move upwards quickly- rocks melt because of adiabatic decompression melting. Now that you understand what that means, you have a great science phrase to impress your friends with at that next party.

But what about subduction zones, places where plates converge? The mantle melts at subduction zones because of the addition of volatiles, such as water and carbon dioxide. It turns out, if you add water, carbon dioxide, or another volatile to a rock, it will melt at a much lower temperature than normal. To put it simply, the large volatiles sort of interrupt the normal chemical bonds in the rock and make it easier to break apart that rock and turn it from solid to liquid. At a subduction zone, a plate (usually an oceanic plate) is going deep into the Earth. When this plate subducts, it brings volatiles with it into the mantle– for instance, water stored in deep-sea sediments. When the subducting plate is heated as it plunges into the hot, deep mantle, these volatiles are released and travel upwards since they are buoyant. The volatiles lower the melting temperature of the rock above the subducting plate and this rock melts, forming volcanoes above the subduction zone.

The wonderful diagram below (from Wikipedia Commons) explains how melts are produced in the Earth. The geotherm is the rate at which the temperature changes with depth in the Earth. The solidus is the line below which the mantle is solid. Above this line, the mantle starts to melt. When the geotherm crosses the solidus, melts are produced.

In the normal case, the solidus and the geotherm do not cross and no melting (and thus no volcanism) is produced. When plates diverge, mantle material rises and decompresses- the mantle melts because it encounters a lower pressure. When plates converge and subduction occurs, the subducting plate releases volatiles (such as water and carbon dioxide) and these volatiles lower the solidus temperature and the mantle melts. At hotspots, the geotherm is higher (by about 100-200 degrees C) and melting is able to occur.

 

Excellent diagram showing the three ways that melts are produced on Earth. Click to view larger. From Wikipedia Commons here.

Finally, why do earthquakes occur at subduction zones such as Japan? Well, any place where tectonic plates move past one another will occasionally experience earthshaking. Earthquakes occur where plates move apart (such as at mid-ocean ridges), slide past each other (such as at the San Andreas fault), or converge and subduct (such as at Japan). The movement of the plates- especially if sudden- has the potential to create very large earthquakes. Something that is unique about subduction plate boundaries (relative to convergent and transform- or sliding- plate boundaries) is that there can be very deep earthquakes.

Here is a comparison of earthquakes and tectonic plate boundaries:

Worldwide earthquake distribution. Figure from Tasa Graphics. Click to view larger.
Worldwide Plate Boundaries. Figure from Tasa Graphics. The little triangles indicate a subduction zone boundary. Click to view larger.

Notice how deep earthquakes occur at subduction zones:

Worldwide distribution of earthquake depth. Figure from Tasa Graphics. Click to view larger.
Depth of earthquakes at a subduction zone. Figure taken from here. Click to view larger.

Finally, below is a figure showing why Japan is an especially tumultuous region of plate convergence. Near the recent earthquake location, three tectonic plates are interacting! The interaction of these three plates makes large earthquakes, such as the recent 8.9 magnitude one, a likely occurrence.

Three tectonic plates in Japan. Figure taken from here. Click to view larger.

A Poor Disaster in a Rich Country

With at least 75 people dead and extensive damage throughout the city of Christchurch, the toll of the recent New Zealand earthquake is already a heavy one. A number of factors contributed to make this earthquake so deadly– the magnitude, the closeness of the epicenter to Christchurch, the shallowness of the epicenter, the time of day, and the fact that much damage from the September 2010 Christchurch earthquake had yet to be repaired.  The death toll and damage caused by the recent earthquake in first world New Zealand is nothing like what occurs when large earthquakes hit third world countries, such as Haiti in January 2010, but for a first world country the destruction is fairly high.

I hope that New Zealand recovers quickly and that the earth-shaking quiets down long enough for proper rebuilding. A geologist colleague of my fiance is currently in New Zealand, just outside of Christchurch, and he told us, “the place is like a warzone.” He’s not sure when he’ll back able to make it home (to South Africa), but he says he just feels lucky to be alive.

Thinking about the toll of the recent New Zealand earthquake, I was reminded of an essay about “rich and poor disasters” that I wrote a few years back.

I don’t want to distract from the all the devastation that recently occurred in New Zealand, but I think Hurricane Katrina is a good example to ponder when considering what factors– both geologic and socioeconomic–affect the toll of natural disasters and the eventual recovery– or lack thereof– of a region from a natural disaster.

A boy bikes past homes unrepaired since Hurricane Katrina, on the eve of the storm’s five year anniversary in the Lower Ninth Ward of New Orleans. Image from Reuters: Lee Celano.

A few weeks ago [note: in 2007] I listened to a talk by John Mutter, a geologist at Columbia University. Mutter has two roles at Columbia. First, he is a geophysist in the Lamont-Doherty Earth Observatory doing traditional research in marine geology and seismology. Second, he is a faculty member in Columbia’s Earth Institute doing research on the links between Earth Science and Social Science.

Mutter researches how climate and the natural landscape play a role in determining economic prosperity and social vulnerability to natural disasters. For instance, a country that is located far from the coast and is very mountainous (for instance, some central African countries) have trouble developing because the cost of transporting goods is high, making the development of trade difficult. Similarly, in places where natural disasters occur with high frequency (recurring Earthquakes, hurricanes, tsunamis, droughts, and so forth), societies often have trouble developing. Societies which are already wealthy generally do better in recovering from natural disasters. However, societies which are poor have trouble recovering. If a poor society is unable to recover from one natural disaster by the time the next one hits, then the society may end up on a downward economic spiral.

Poor societies often have more trouble recovering from natural disasters because they generally have fewer emergency resources. For instance, poor societies have limited emergency responses such as medics and firefighters. Poor societies may also have limited or no early warning systems and may have less stringent building codes. After a disaster, a poor society may have limited funds to distribute for rebuiling. Most people probably do not have insurance on their houses, boats, cars, and other possessions. All of these factors mean that when it comes to natural disasters and also climate change, the poor suffer more than the wealthy. More people die, more property is lost, and less is done after the disaster.

John Mutter’s talk touched on the links between economics and the natural world. He also presented the basics on the differences in how poor and rich societies respond to and recover from natural disasters. However, Mutter’s talk was primarily focused on the recent Hurricane Katrina disaster. Mutter argues that in terms of death toll and damage, the Katrina disaster looked like a poor world disaster. That is, a poor world disaster occurred in an overall wealthy country.

Mutter argues, and I tend to agree with him, that Hurricane Katrina should not have happened in a first world country. Too much damage was done, and too many people died. The warnings and evacuation orders came too late, and many people did not have the resources to get out of town. Not enough has been done after the disaster to help New Orleans recover. While affluent neighborhoods and tourist attractictions are largely rebuilt in New Orleans, many of the poor neighborhoods still resemble wastelands. The Hurricane Katrina disaster highlights one of America’s weak points: while an affluent country, overall, there are cities such as New Orleans where extreme poverty remains.

As an affluent (well, I manage to live okay off my grad school stipend) white woman living in hoity-toity Cambridge*, I can easily forget about these inequities. Aside from a few homeless people I walk by now and then in Harvard Square, I don’t interact with poor people on regular basis– or at least, I’m not aware of it. Similarly, I can easily become wrapped up in my scientific research and forget about people. I really enjoyed Mutter’s talk. First, I really enjoy the interdisciplinary nature of his research. Second, I think the Hurricane Katrina disaster is a good (or bad, perhaps?) way to put a spotlight on some of the economic and social stratifications here in America. America, overall, is a wealthy country. As one forceful hurricane shows, however, America– or at least her poor– is still vulnerable in many ways.

For those interested in exploring this topic more, here are some useful links:
The Earth Institute at Columbia University
An Article by Mutter on Hurricane Katrina
John Mutter’s Katrina Project Website

*I now live in hoity-toity Woods Hole.

Some Links and Videos Related to the New Zealand Earthquake

Many geobloggers and news agencies have been reporting on the recent magnitude 6.3 earthquake that occurred in Christchurch, New Zealand about six hours ago. This initial earthquake was quickly followed by two magnitude >5.5 earthquakes.

There has been some incredible damage and the latest report is that at least 65 people have died.

Below are a few links and videos related to the recent earthquake.

Here are some links from the geoblogosphere:
Highly Allochthonous: Magnitude 6.3 earthquake rocks Christchurch

Eruptions: Another sizable earthquake in Christchurch, New Zealand

The Landslide Blog: First news of the Mw=6.3 earthquake in Christchurch, New Zealand

Here are some links from news agencies:
New Zealand Herald: Updates on fatalities and damage; pictures, and videos

New York Times: Latest update

CNN: Latest update

Finally, here are a few videos, all taken from youtube. Just a warning that some of the footage is graphic and disturbing. These videos show the devastating destruction that results when a large earthquake hits a highly-populated area.

From TV New Zealand:

From  the Associated Press:

From CNN: