Constant quakes: Life on the edge (of a divergent plate boundary)
The image at left represents all of the earthquakes in Iceland in the last 48 hours as of the writing of this article. Can you guess how many there were? 15? 37? 111. Icelandic Seismicity While that may seem incredible, for contrast there were nearly twice as many in California in the same time span. USGS Earthquake tracker Most of these quakes are very small, less than magnitude 1, and are not dangerous. But the Earth's surface is in a constant state of change. Earthquakes are our evidence of this. In a place like Iceland, where a tectonic plate boundary is a defining feature (really THE defining feature in Iceland) nothing less than constant seismic activity can be expected. The reassuring news for the people of Iceland is that a divergent plate boundary is the least likely to produce a lethal earthquake.
In a strike-slip fault where two plates slide past each other, like the San Andreas in California, energy is built up over decades or centuries as the two plates attempt to move past each other. In a divergent plate boundary, (like the one under Iceland) the plates moving away from each other are less capable of storing energy before releasing it in earthquakes. This isn't to say that Iceland goes unprepared. University of Iceland: earthquake research projects They have an extensive emergency response network, trained and ready to deal with earthquakes as well as volcanic eruptions. Icelandic civil protection bureau Iceland as a nation also has one of the strictest building codes in regards to their resistance to seismic motion. Details on Icelandic earthquake-proofing I think it's safe to say the Icelandic people have a very real understanding of, and practical and extensive approach to, the natural hazards of their island.
Hi, Brendan!
ReplyDeleteReally interesting entry about earthquakes in Iceland! I read a little bit on Iceland (you definitely sparked my curiosity) and found out, just like you pointed out that Iceland is located at a divergent plate boundary over the Mid-Atlantic Ridge, along which the North American Plate and Eurasian Plate are being pushed apart by newly formed crust. I also read that a deep-seated mantle plume is also present in the area and interacts with the North American Plate and that this plume (or hotspot) and the active spreading axes are producing the volcanism of present day Iceland. In contrast to Iceland's volcanos, Romanian ones are the result of a convergent plate margin/boundary, which we can arguably say that it is "most varied" in the geological phenomena that it can trigger, including potentially lethal, large magnitude earthquakes. But going back to Iceland, I do recall the eruption of the Eyjafjallajökull Volcano in April 2010 which caused plane traffic to be either diverted or cancelled all together in Northwestern Europe because of the massive ash cloud that ensued as a result of the eruption. According to what I read that massive ash cloud from the volcanic eruption in Iceland became visible even in the Northern part of Romania. Iceland must be quite spectacular!
absolutely! It is a little less threatening than some other geologic hotspots (Japan, or Southern California for example) but it is not without it's dangers. An eruption in 1783 known as the "Laki" eruption, put out so much sulfur dioxide that it lowered the Earth's temperature, and created such famine and toxicity on the island itself that nearly one quarter of the population died... I think we have seen just a small piece of what the volcanism here can do. Thank you for your comments Camelia, I'm so glad to have sparked your interest and I always enjoy our interactions. I look forward to hearing and reading more from you in the coming weeks. :)
DeleteRealized I forgot to answer your question; I would assume in the last 48 hours there were 37 earthquakes in Iceland. Am I close or not really?
ReplyDelete111 :)
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