Discover and read the best of Twitter Threads about #platetectonics
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The Earth's most common elevation is sea level - and yet, most of Earth's surface lies below sea level - FAR below sea level, at 4-6 km depth.
Why?
The answer is a combination of #platetectonics and Earth's oceans. 1/9
#tectoplot
Why?
The answer is a combination of #platetectonics and Earth's oceans. 1/9
#tectoplot
You might think that the oceans are just parts of the land that are covered with water. Actually, that's really not the point - the oceans are there because the rocks *below* the oceans are fundamentally different from those below continents - and it's all because of magma! 2/9
Below the crust, the mantle is convecting. This is driven by heat given off by radioactive delay deep inside the Earth.
The mantle is solid rock - but every now and then a pocket melts: due to the addition of water, release of pressure, or extra added heat. Magma! 3/9
The mantle is solid rock - but every now and then a pocket melts: due to the addition of water, release of pressure, or extra added heat. Magma! 3/9
Daily Bookmarks to GAVNet 08/16/2021 greeneracresvaluenetwork.wordpress.com/2021/08/16/dai…
Scientists Pin Down When Earth’s Crust Cracked, Then Came to Life
quantamagazine.org/scientists-pin…
#geology #PlateTectonics #life #evolution #origin
quantamagazine.org/scientists-pin…
#geology #PlateTectonics #life #evolution #origin
Next generation electronics: Expanding the possibilities with silver nanowires
phys.org/news/2021-08-e…
#electronics #nanowire #TechnologyDevelopment #materials
phys.org/news/2021-08-e…
#electronics #nanowire #TechnologyDevelopment #materials
The #SouthSandwichIslands are a wonderful example of #platetectonics in miniature. The #SouthAmericanPlate is subducting west at ~7 cm/yr below the #SandwichPlate; this #subductionzone hosted a Mw7.5 #earthquake yesterday (Aug 12). 1/4
#tectoplot
#tectoplot
The depth of the #earthquake is still poorly constrained. GFZ puts it shallow, above the plate interface, dip 11°. USGS puts it deeper, within the slab, dip 26° and non-double-couple. Historical events of this scale in the region are old so not much help - 1929, 1933, 1964. 2/4
Given the curvature of the #subductionzone, it would certainly be reasonable to have some intra-slab deformation, and fracturing could be complex, leading to non-double-couple. The closest large event (1964) was apparently quite deep (125 km). 3/4
The Great Alaska Earthquake occurred on March 27, 1964 and rocked the state with strong ground shaking that lasted four and a half minutes. #AlaskaEarthquake #earthquake
At M9.2, it was the 2nd largest quake ever recorded. This event also rocked the scientific community by confirming a major principle of #platetectonics with the observation that the oceanic Pacific Plate dives beneath the continental North American Plate at the Aleutian trench.
On average, #Alaska has 24,000+ measured earthquakes every year. Usually, there is at least one M7 every year. Between 1899 and 1986, eight #earthquakes of M8 or greater impacted different areas of the Aleutian subduction zone.
This is our new #outreach tool to explain #geology - moving wooden model of #platetectonics! Developed by @GFU_AVCR
@GFU_AVCR @PrirodovedciCZ, @zpravyrozhlascz @CzechTV @Aktualnecz : this may be interested for you. It is worldwide unique didactic tool ;)
@GFU_AVCR : and if you would like to see it how does it work, see
