Alaska just had a big earthquake and a tsunami warning but there was no tsunami which probably means the Pacific plate which is being driven under the North American Plate didn’t have any great change in status. That is, nothing really happened except deep down, not at the surface. No subsidence or oceanic landslides. Looking at the data, the earthquake was probably too deep in the earth to cause these sorts of changes which cause tsunamis.
As some of the biggest tsunamis in the last 1,000 years happen right after each other (geologically speaking), scientists have been able to gather a tremendous amount of information about these sorts of events, information that was lacking before this. When The Great Alaskan Earthquake & Tsunamis of 1964 happened, there was no published work on plate tectonic movements. Subduction zones were virtually unknowable back then because there was no intellectual framework to use as a tool to understand why there were these subduction zones in the first place.
The tsunami took Alaska by surprise. The idea of subsidence after a quake was also a big surprise. This event actually drove forwards the researchers who were trying to find some means of proving their contention that the earth’s continents were quite mobile rather than fixed in place. It gave obvious proof of the forces of nature that can be suddenly unleashed by earthquakes.
Today’s earthquake was right along the subduction zone between Alaska and Siberia. This coming on the heels of the Great Honshu quake offshore of Japan’s North American plate section shows us that the Pacific Plate’s movements can have some sort of coordinated effects. That is, when stress was relieved offshore of Japan, this has caused stress to also be relieved at other rim areas. Perhaps the repositioning of the entire perimeter of the north and western edges of this huge plate is now being played in geological fast forward speed rather than these all being isolated events?
Here is a map of the most recent Pacific Plate subduction zone quakes: Alaska Region
Note the line of quakes along the mountainous backbone of Alaska. Virtually no quakes except for the recent 7.2 event are occurring along the subduction zone. Instead, these quakes are happening well away from it. From Fairbanks all the way down to Anchorage and then along the line of volcanoes, we see frequent small tremors. Just like with Japan, for example, or South America and North America, all the volcanoes are set back from subduction zones.
On the other hand, if we look at the map below of global hot spots, we see some interesting differences. For example, the Azores and Iceland hot spots coincide exactly with the Mid-Atlantic Ridge where the plates are spreading apart, not shoving under continental masses. Other volcanic island groups are along the spreading ridges south of Africa and in the Indian Ocean where the fast-moving Indian Plate is spreading northwards. The Galapagos Islands are another example of plate spread where there is a hot spot. Otherwise, the remaining hot spots are in the center of the Pacific Plate, the center of Africa and one mega-site in the middle of the North American Plate.
Figure 2. Map showing locations of geologic hotspots. Notice how many of them are located away from plate boundaries. (Source: United States Geological Survey-USGS: The source of this map and links to more information regarding geologic hotspots are found athttp://pubs.usgs.gov/gip/dynamic/world_map.html)
Eurasia has no hot spots at all. Neither does South America or Australia. Some scientists and I agree with this assessment, believe hot spots are actually signs of very ancient but also very severe asteroid damage to the mantle. The number of these clustered along the central girdle of the planet may be proof of this but this is still all very subjective information. Back to the recent Alaskan earthquake:
The Fox Islands are quite volcanic and note how this earthquake is next to the volcanoes, not directly on the subduction zone itself. Alaska Volcano Observatory – Activity
The quakes were with the smaller volcanoes of this long, long chain. Amukta is only 2,500 feet above sea level whereas the much bigger Cleveland volcano is over 5,600 feet tall. If we look at the earthquake data for this last week we can see that the earth’s disturbances are across a broad spectrum of depths.
Note the smaller quakes before the big one and then the aftershocks. The depths are quite variable, too. From over 160 km deep to 10 km. This means there has been some major deep changes even though nothing happened much at the surface. Could this be a sign that magma is moving upwards? So little is still understood about volcanic eruptions and earthquakes like this. Sometimes, frequent quakes are preludes to major eruptions.
This is a very pressing matter since Tokyo is in the shadow of a major, one of the bigger volcanoes on earth! Will it erupt in the next 5 years is a life and death question for the Japanese. A major eruption at Amukta, on the other hand, won’t destroy large population centers but it could affect the climate if it is as big an eruption as the one in Chile.
Already, the dust cloud from that eruption is causing the atmosphere to cut down on solar penetration to the degree that there are now very red sunsets. These are quite beautiful to see but also a sign that winter there will get much colder: Chilean Volcano Colors Southern Hemisphere Skies. Also, AFP: Experts warn Chile volcano could explode again since there is this ‘plug’ in the volcano. This is very dangerous because the volcanic eruptions that change evolution and climate tend to be volcanic explosions as volcanoes destroy themselves and everything around them.
We know now that the massive eruption in Santorini nearly 4,000 years ago annihilated one of the finest civilizations at that time (and probably for thousands of years!) and the eruption of the volcano on the border of China and North Korea may have impelled many Koreans to flee to Japan, thus launching a new culture there. Volcanic eruptions may have caused homo sapiens to leave Africa and move across Eurasia, killing all the hominids there, 70,000 years ago.
All of this is due to the Speed of the Continental Plates. Here is a chart showing absolute velocity and this shows clearly that the two fastest moving plates are the Cocos Plate and the Pacific Plate. The Cocos Plate is moving in the opposite direction as the Pacific Plate and the subduction zone there is what created the entire Central American mountains and volcanoes as this plate shoves into the Caribbean Plate which has seen a rim-full of earthquakes since the Great Haiti Quake.
This quake still has half of the population either homeless or living in severely damaged buildings on the verge of collapse. The financial chaos and poverty has not abated and very little has been rebuilt. In contrast, Japan quake caused almost $200b damage and a severely deep in debt government which is too shy to tax some of the richest people on earth can’t afford to rebuild easily. With Fukushima destroying everything in its vicinity just as nasty as any volcano, that ongoing disaster is not over at all and here is the latest news from that mess: Suspected failure to vent Fukushima reactor casts doubt on accountability standards – The Mainichi Daily News
TEPCO had claimed that it had successfully vented the plant’s No. 1 reactor to decrease pressure inside it prior to a hydrogen explosion, and the government had supported the power supplier’s claim…However, the pressure still remained above the designated upper limit of 427 kilopascals and rose moderately after the announcement. Moreover, the monitoring post on its premises showed no signs of radioactive materials being released out of the reactor following the venting attempt. TEPCO insiders say they were unable to confirm that the valve for venting had opened. Both TEPCO and the government could have checked whether the venting was successful on many occasions. Nevertheless, the government simply mimicked TEPCO’s comments…
Again: if one of the most developed and educated economies on earth cannot cope with earthquakes, tsunamis, or deal with nuclear disasters, who else can do this better? The answer is obvious: humans are incapable of handling nuclear disasters of any sort. Once they get out of control, this is fatal.
Volcanoes are earth’s way of relieving the stress of plate tectonic movements. From the earth’s perspective, volcanic eruptions are a good thing. Fertilizes the land. Adds much needed CO2 to the atmosphere (look, I am thinking like a tree, not a human, here!) and it builds up landmasses which are constantly being eroded by rain, ice and wind. Like anything in nature, the good and bad are in this bundle. We have to remember both are occurring at the same time. I find this most interesting, by the way.
Far from being a disorganized mess, the evolution of life on earth depends on a CHANGING EARTH. A CHANGING CLIMATE, and in general, a degree of chaos. This, in particular, scared me about fellow humans: they want to freeze time and space in some present ideal because changes annoy us.
Even as we change things, we want other things to literally freeze in place! A mere 2 million years ago, for example, Greenland was green with trees and grass and had many animals living there. They all died! It became this frozen ice sheet a mile thick. Terrible end to what was once a fair continent! Ditto, earlier, for Antarctica which was tree covered, too. The present status quo is considerably colder than 2 million years ago.
Over the eons, not only have the continents moved restlessly about the planet, the coasts have shifted tremendously not to mention, the amount of ice has changed radically and for mysterious reasons, too. We evolved due to these changes and we can’t do what Dr. Faustus tried to do: stop time. Remember, the deal with Mephistopheles was this: Dr. Faustus would be seized and taken to hell the minute he says, ‘Stop, may this moment go on forever!’ The desire to have a happy medium that pleases continue forever is actually death. A harsh statement but I fear, a very true picture of reality.
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