Why was the Haiti Earthquake was not predictable?
in [Relativity]
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From: J. Clarke on 20 Jan 2010 10:50 jmfbahciv wrote: > J. Clarke wrote: >> jmfbahciv wrote: >>> BradGuth wrote: >>>> On Jan 18, 11:01 am, John Stafford <n...(a)droffats.ten> wrote: >>>>> In article <hj1uim42...(a)news7.newsguy.com>, jmfbahciv >>>>> <jmfbahciv(a)aol> wrote: >>>>> >>>>>> BradGuth wrote: >>>>>>> How much did Haiti near ground zero rise or fall? >>>>>> I figured the quake was volcanic and not a slip of faults. >>>>>> Are you saying that the mountain separaing the two countries >>>>>> is from two plates rather than a volcano? Maybe the island >>>>>> I'm remembering was a different island. >>>>> It was a strike-slip quake. No significant rise or fall. >>>> In other words, the buoyancy of Haiti is roughly the same, and >>>> unlike Yellowstone, there's no build-up of any gas or magma bubble >>>> that's looking for a way out. >>>> >>> Huh? You think islands float? They're not a dessert. >> >> Specific gravity of granite is around 2.7, basalt around 3, olivine >> about >> 3.3, so yes, islands float on the mantle. >> > I thought islands were the acne of the plates caused by either > volcanic holes in the plate or plates mushing up against each > other (like two flat pieces of Play-dough). So an island > can be similar to those big rocks which would eventually show > up on the ground in my backyard in Massachusetts? I always > thought that had more to do with a large lump getting joggled > among smaller lumps. Some, like the Hawaiian Islands, are the result of vulcanism, some are the remains of mountains formed where plates collide, some are the result of coral growth. Regardless they're a mass of lighter rock floating on top of the mantle, for certain values of "lighter" and "floating". And this is approaching the limits of my knowledge of geology.
From: BradGuth on 20 Jan 2010 12:49 On Jan 20, 7:39 am, jmfbahciv <jmfbahciv(a)aol> wrote: > BradGuth wrote: > > On Jan 19, 8:49 am, "J. Clarke" <jclarke.use...(a)cox.net> wrote: > >> jmfbahciv wrote: > >>> BradGuth wrote: > >>>> On Jan 18, 11:01 am, John Stafford <n...(a)droffats.ten> wrote: > >>>>> In article <hj1uim42...(a)news7.newsguy.com>, jmfbahciv > >>>>> <jmfbahciv(a)aol> wrote: > >>>>>> BradGuth wrote: > >>>>>>> How much did Haiti near ground zero rise or fall? > >>>>>> I figured the quake was volcanic and not a slip of faults. > >>>>>> Are you saying that the mountain separaing the two countries > >>>>>> is from two plates rather than a volcano? Maybe the island > >>>>>> I'm remembering was a different island. > >>>>> It was a strike-slip quake. No significant rise or fall. > >>>> In other words, the buoyancy of Haiti is roughly the same, and unlike > >>>> Yellowstone, there's no build-up of any gas or magma bubble that's > >>>> looking for a way out. > >>> Huh? You think islands float? They're not a dessert. > >> Specific gravity of granite is around 2.7, basalt around 3, olivine about > >> 3.3, so yes, islands float on the mantle. > > > Thank you so very much for what's obvious to some and apparently > > incomprehensible to so many others, that we're floating on what might > > be considered an ocean of mantle with a highly liquefied frosting of > > magma. > > It was not obvious to me. I had interpreted your comment to be > saying that the island was by itself floating like a floating > island dessert. Hence, my comment. It is still doesn't seem > likely, as in my common sense, that the island is floating by > itself separate from the rest of the land (under the sea) around it. > > Now I am confused and am suspecting that I just stubbed my toe > on something I didn't know I didn't know. Kewl. > > > > > Mantle (extensively of silicates and iron) 3.5<5.75 g/cm3 offers a > > great deal of crust buoyancy. > > But those islands aren't stand-alone. Are they? > > /BAH Islands of basalt crust are never entirely alone, as being essentially 100% packed up against other islands of crust. Trust me, that's a good thing. Question: is the outer crust of Earth expanding or contracting as it cools? The entire crust of Earth, as massive and dense as it is, essentially floats on a mantel of <5.75 g/cm3, that's frosted with fluid ocean of magma that's worth ~3.5 g.cm3. The average basalt crust density of perhaps <3.3 g/cm3 leaves us with >0.2 g/cm3 worth of buoyancy (let us say 0.25 g/cm3). The relatively thin crust of Earth (roughly a fifth that of our moon) has also been badly broken and shifting about for quite some time, and our trusty moon(Selene) is simply most responsible for keeping it that way. However, the solidified basalt crust of our moon is not broken, and forms a continuous outer sell like structure that could be vapor tight enough to hold considerable internal pressure, and conceivably even brine/water as well as crystal populated geode pockets that could conceivably accommodate every human on Earth, with volume to spare. ~ BG
From: BradGuth on 20 Jan 2010 12:53 On Jan 20, 7:50 am, "J. Clarke" <jclarke.use...(a)cox.net> wrote: > jmfbahciv wrote: > > J. Clarke wrote: > >> jmfbahciv wrote: > >>> BradGuth wrote: > >>>> On Jan 18, 11:01 am, John Stafford <n...(a)droffats.ten> wrote: > >>>>> In article <hj1uim42...(a)news7.newsguy.com>, jmfbahciv > >>>>> <jmfbahciv(a)aol> wrote: > > >>>>>> BradGuth wrote: > >>>>>>> How much did Haiti near ground zero rise or fall? > >>>>>> I figured the quake was volcanic and not a slip of faults. > >>>>>> Are you saying that the mountain separaing the two countries > >>>>>> is from two plates rather than a volcano? Maybe the island > >>>>>> I'm remembering was a different island. > >>>>> It was a strike-slip quake. No significant rise or fall. > >>>> In other words, the buoyancy of Haiti is roughly the same, and > >>>> unlike Yellowstone, there's no build-up of any gas or magma bubble > >>>> that's looking for a way out. > > >>> Huh? You think islands float? They're not a dessert. > > >> Specific gravity of granite is around 2.7, basalt around 3, olivine > >> about > >> 3.3, so yes, islands float on the mantle. > > > I thought islands were the acne of the plates caused by either > > volcanic holes in the plate or plates mushing up against each > > other (like two flat pieces of Play-dough). So an island > > can be similar to those big rocks which would eventually show > > up on the ground in my backyard in Massachusetts? I always > > thought that had more to do with a large lump getting joggled > > among smaller lumps. > > Some, like the Hawaiian Islands, are the result of vulcanism, some are the > remains of mountains formed where plates collide, some are the result of > coral growth. Regardless they're a mass of lighter rock floating on top of > the mantle, for certain values of "lighter" and "floating". And this is > approaching the limits of my knowledge of geology. Your geology limits are several thousand percent better than the average Usenet/newsgroup dysfunctional contributor has to offer. How about a little help with understanding the geology of our moon, as well as the planet Venus? ~ BG
From: BradGuth on 20 Jan 2010 13:18 On Jan 18, 7:37 am, jmfbahciv <jmfbahciv(a)aol> wrote: > J. Clarke wrote: > > jmfbahciv wrote: > >> BradGuth wrote: > >>> On Jan 16, 7:33 am, jmfbahciv <jmfbahciv(a)aol> wrote: > >>>> tadchem wrote: > >>>>> On Jan 13, 11:32 am, Sanny <softtank...(a)hotmail.com> wrote: > >>>>>> Why was todays, Haiti Earthquake not predictable? > >>>>>http://ca.news.yahoo.com/s/capress/100115/science/science_us_haiti_ea... > >>>> Why is all the news about Haiti? Didn't Santo Domingo get an > >>>> earthquake? > > >>>> /BAH > >>> Whenever that moon gets aligned, and worse yet if this included the > >>> planet Venus, there's lots of earthquakes to pick from. > > >> Huh? I was talking about the country which is on the other > >> half of that island. > > > You expect BradGuth to actually know some geography? > > Yea. Guess I was being stupid again ;-). > > /BAH Islands of our thin basalt crust are never entirely alone, as being essentially 100% packed up against other islands of crust. Trust me, that's a very good thing. Question: is the outer crust of Earth expanding or contracting as it cools? The entire crust of Earth, as massive and dense as it is and solidifying at roughly 1 mm/century, essentially floats on a mantel of <5.75 g/cm3 that's frosted with fluid ocean of magma that's worth ~3.5 g.cm3. The average basalt crust density of perhaps <3.3 g/cm3 leaves us with >0.2 g/cm3 worth of buoyancy (let us say 0.25 g/cm3) to work with, giving our crust roughly a volumetric 7.5% buoyancy factor. The relatively thin crust of Earth (roughly a fifth that of our moon) has also been badly broken and shifting about for quite some time, and our trusty moon(Selene) is simply most responsible for keeping it that way. However, the solidified basalt crust of our moon is not broken, and forms a continuous outer sell like structure that could be vapor tight enough to hold considerable internal pressure, and conceivably even including brine/water as well as hosting crystal populated geode pockets that could conceivably accommodate every human on Earth, with volume to spare. ~ BG
From: HVAC on 20 Jan 2010 14:21
"jmfbahciv" <jmfbahciv(a)aol> wrote in message news:hj773d02sbg(a)news5.newsguy.com... >> > I thought islands were the acne of the plates caused by either > volcanic holes in the plate or plates mushing up against each > other (like two flat pieces of Play-dough). So an island > can be similar to those big rocks which would eventually show > up on the ground in my backyard in Massachusetts? I always > thought that had more to do with a large lump getting joggled > among smaller lumps. There's a great series on The History Channel (a rarity) called "How The Earth Was Made". They go into great detail about tectonic plate interactions and other geological phenomenon. |