{"id":1326,"date":"2024-09-05T20:05:51","date_gmt":"2024-09-05T18:05:51","guid":{"rendered":"https:\/\/test.kint.cz\/?p=1326"},"modified":"2025-06-04T18:29:59","modified_gmt":"2025-06-04T16:29:59","slug":"geodynamika-zeme","status":"publish","type":"post","link":"https:\/\/test.kint.cz\/sk\/geodynamika-zeme\/","title":{"rendered":"Geodynamika Zem\u011b"},"content":{"rendered":"\t\t
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Geodynamika Zem\u011b<\/h1>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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Z\u00e1klady stavby zemsk\u00e9ho t\u011blesa a Geodynamika<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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Geodynamika se zab\u00fdv\u00e1 v\u00fdzkumem planet a jejich v\u00fdvoji. Je sou\u010d\u00e1st\u00ed n\u011bkolika v\u011bdn\u00edch discipl\u00edn jako je nap\u0159. geologie, fyzika, biologie a chemie a propojuj\u00ed je pr\u00e1v\u011b geofyzika, geochemie, paleontologie, sedimentologie, strukturn\u00ed geologii a dal\u0161\u00ed. Pro pot\u0159eby bezpe\u010dnosti, tj. pro zaji\u0161t\u011bn\u00ed bezpe\u010d\u00ed lid\u00ed, n\u00e1s zaj\u00edm\u00e1 p\u0159edev\u0161\u00edm geologie Zem\u011b.<\/p>

K pops\u00e1n\u00ed problematiky geologie n\u00ed\u017ee v textu (v\u010detn\u011b obr\u00e1zk\u016f) jsme vych\u00e1zeli p\u0159edev\u0161\u00edm ze zdroje:<\/p>

POSP\u00cd\u0160IL, Lubomil. Geofyzika a geodynamika. Modul #1, Studijn\u00ed opory pro studijn\u00ed programy s kombinovanou formou studia. Brno: VUT v Brn\u011b Fakulta stavebn\u00ed 2007<\/p>

a<\/p>

informac\u00ed z re\u0161er\u0161\u00ed v p\u0159edchoz\u00edm \u010dl\u00e1nku\u00a0Geofyzika (kint.cz)<\/a><\/p>

Doporu\u010dujeme tak\u00e9 sledovat populariza\u010dn\u00ed \u010dl\u00e1nky a p\u0159\u00edsp\u011bvky dr. Petra Bro\u017ee\u00a0Petr Bro\u017e \u2013 Geofyzik\u00e1ln\u00ed \u00fastav Akademie v\u011bd \u010cR, v.v.i. (cas.cz)<\/a><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Fyzik\u00e1ln\u00ed charakteristika Zem\u011b<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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Fyzik\u00e1ln\u00ed vlastnosti zemsk\u00e9ho t\u011blesa jsou m\u011b\u0159iteln\u00e9, proto s dostate\u010dnou p\u0159esnost\u00ed zn\u00e1me jeho rozm\u011br, tvar, hmotu, t\u00edhov\u00e9 i magnetick\u00e9 pole, geomagnetick\u00fd tok a dal\u0161\u00ed. Zemsk\u00e9 nitro m\u016f\u017eeme m\u011b\u0159it pouze nep\u0159\u00edmo pomoc\u00ed seismick\u00fdch vln (zem\u011bt\u0159esen\u00ed) pronikaj\u00edc\u00ed strukturou zem\u011b tak jako rentgenov\u00e9 paprsky.<\/p>

Povrchov\u00e9 tvary Zem\u011b dle zdroje\u00a01<\/a><\/sup><\/em><\/strong>:<\/p>

kontinenty<\/em><\/strong>\u00a0\u2013 tvo\u0159\u00ed pevnina, kontinent\u00e1ln\u00ed \u0161elf (sklon cca 0\u00b007 \u0301, s hloubkou 20 a\u017e 550 m) a zatopen\u00fd kontinent\u00e1ln\u00ed stupe\u0148 (sklon cca 5\u00b0); \u00bc plochy kontinent\u016f je tedy zakryt\u00e1 vodou; na kontinentech lze sledovat n\u00e1sleduj\u00edc\u00ed strukturn\u00ed jednotky:<\/p>

1. prekambrick\u00e9 \u0161t\u00edty,<\/p>

2. platformy,<\/p>

3. p\u00e1semn\u00e1 poho\u0159\u00ed prost\u00edraj\u00edc\u00ed se pod\u00e9l orogenetick\u00fdch p\u00e1sem ve zvr\u00e1sn\u011bl\u00fdch hornin\u00e1ch (viz n\u00e1sleduj\u00edc\u00ed obr\u00e1zek);<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Topografie zemsk\u00e9ho povrchu: \u010derven\u00e9 \u2013 \u0161elfov\u00e9 oblasti, \u017elut\u00e1 na kontaktu s \u010dervenou \u2013 kontinent\u00e1ln\u00ed stupn\u011b, zelen\u00e1 \u2013 platformy a prekambrick\u00e9 \u0161t\u00edty, b\u00e9\u017eovo\/hn\u011bd\u00e9 p\u00e1sma \u2013 orogenn\u00ed p\u00e1sma, mod\u0159e hlubokomo\u0159sk\u00e9 p\u00e1nve, sv\u011btlezelen\u00e1 a\u017e \u017elut\u00e1 \u2013 st\u0159edo-oce\u00e1nick\u00e9 h\u0159bety<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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kontinent\u00e1ln\u00ed okraj<\/em><\/strong>\u00a0\u2013 je oblast mezi kontinentem a oce\u00e1nick\u00fdm baz\u00e9nem (Atlantsk\u00fd typ \u2013 tvo\u0159\u00ed jej kontinent\u00e1ln\u00ed self, svah a \u00fapat\u00ed; Andsk\u00fd typ \u2013 \u00fazk\u00fd kontinent\u00e1ln\u00ed \u0161elf a oce\u00e1nick\u00fd p\u0159\u00edkop hned pod kontinent\u00e1ln\u00edm svahem; typ ostrovn\u00edho oblouku \u2013 poz\u016fst\u00e1v\u00e1 z vulkanick\u00e9ho ostrovn\u00edho oblouku s oce\u00e1nick\u00fdm p\u0159\u00edkopem),<\/p>

oce\u00e1ny \u2013\u00a0<\/em><\/strong>hlubokomo\u0159sk\u00e9 baz\u00e9ny maj\u00ed hloubku cca 6 km, v p\u0159\u00edkopech 9 km a v\u00fdjime\u010dn\u011b a\u017e 11 km; obdobou kontinent\u00e1ln\u00edch poho\u0159\u00ed jsou v prostoru oce\u00e1n jeho\u00a0h\u0159bety<\/em><\/strong>\u00a0s p\u0159ev\u00fd\u0161en\u00edm cca 3 km; uprost\u0159ed oce\u00e1nsk\u00fdch h\u0159bet\u016f se \u010dasto t\u00e1hne prohlube\u0148, tzv.\u00a0rifty<\/em><\/strong>; zv\u00fd\u0161en\u00e1 m\u00edsta oproti hlubokomo\u0159sk\u00fdm\u00a0p\u00e1nv\u00edm<\/em><\/strong>\u00a0jsou tzv.\u00a0kontinent\u00e1ln\u00ed \u00fapat\u00ed<\/em><\/strong>; d\u00e1le se v oce\u00e1nech vyskytuj\u00ed ji\u017e zm\u00edn\u011bn\u00e9 p\u0159\u00edkopy, p\u0159ilehl\u00e9 ostrovn\u00ed oblouky, vulk\u00e1ny a vulkanick\u00e9 h\u0159bety (viz obr\u00e1zek),<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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P\u0159ehled z\u00e1kladn\u00edch deskov\u00fdch rozhran\u00ed a glob\u00e1ln\u00edch tektonick\u00fdch struktur Legenda: Convergent plate boundary \u2013 konvergentn\u00ed (kompresn\u00ed) rozhran\u00ed; Transform plate boundary \u2013 transformn\u00ed (zlomov\u00e9) rozhran\u00ed; Divergent plate boundary \u2013 divergentn\u00ed (extenzn\u00ed) rozhran\u00ed; Continental rift zone \u2013 kontinentaln\u00ed rift (propadlina); Island arc \u2013 ostrovn\u00ed oblouk; trench \u2013 p\u0159\u00edkop; shield volcano \u2013 \u0161t\u00edtov\u00fd vulk\u00e1n.<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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Rozlo\u017een\u00ed vulk\u00e1n\u016f<\/em><\/strong>\u00a0<\/em>na Zemi. 75 % sou\u010dasn\u00fdch \u010di historicky aktivn\u00edch vulk\u00e1n\u016f le\u017e\u00ed pod\u00e9l cirkumpacifick\u00e9ho pruhu (tzv. ohniv\u00fd prstenec).\u00a0Pat\u0159\u00ed do n\u011bj mlad\u00e1 poho\u0159\u00ed z\u00e1padn\u00ed Ameriky a vulkanick\u00e9 ostrovn\u00ed oblouky lemuj\u00edc\u00ed severn\u00ed a z\u00e1padn\u00ed strany Pacifiku. Druh\u00fdm p\u00e1sem je st\u0159edomo\u0159sko-asijsk\u00fd pruh; zde je vulkanick\u00e1 \u010dinnost mnohem \u0159id\u0161\u00ed, s v\u00fdjimkou Indon\u00e9sie s St\u0159edomo\u0159\u00ed. O oce\u00e1nick\u00fdch vulkanick\u00fdch p\u00e1sech jsme se zm\u00ednili v\u00fd\u0161e.<\/em><\/p>

Je t\u0159eba upozornit, \u017ee vulkanick\u00e1 \u010dinnost je t\u00e9\u017e v\u00e1z\u00e1na na riftov\u00e9 syst\u00e9my (v oce\u00e1nech i na kontinentu). Bylo dok\u00e1z\u00e1no, \u017ee 93 % v\u0161ech aktivn\u00edch vulk\u00e1n le\u017e\u00ed pod\u00e9l kru\u017enic, kter\u00e9 by vy\u0165aly 3 vz\u00e1jemn\u011b kolm\u00e9 roviny proch\u00e1zej\u00edc\u00ed st\u0159edem Zem\u011b<\/em>\u00a02<\/a><\/sup>.<\/p>

Rozlo\u017een\u00ed seismick\u00e9 aktivity<\/strong>:<\/em><\/p>

1. M\u011blk\u00e1 zem\u011bt\u0159esen\u00ed s ohnisky do hloubky 70 km<\/em>.<\/p>

2. St\u0159edn\u00ed hlubok\u00e1 s ohnisky mezi 70 \u2013 300 km.<\/em><\/p>

3. Hlubok\u00e1 zem\u011bt\u0159esen\u00ed s ohnisky mezi 300 \u2013 700 km hluboko.<\/em><\/p>

V cirkumpacifick\u00e9m p\u00e1su le\u017e\u00ed 80 % v\u0161ech m\u011blk\u00fdch, 90 % st\u0159edn\u00edch a t\u00e9m\u011b\u0159 v\u0161echna hlubok\u00e1 zem\u011bt\u0159esen\u00ed. Zb\u00fdvaj\u00edc\u00ed zem\u011bt\u0159esen\u00ed se vyskytuj\u00ed ve st\u0159edomo\u0159sko-asijsk\u00e9m pruhu a ve sv\u011btov\u00e9m riftov\u00e9m syst\u00e9mu<\/em>\u00a03<\/a><\/sup>.\u00a0<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Seismologie a Zemsk\u00e9 nitro<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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Seismologie studuje zam\u011bt\u0159esen\u00ed a to p\u0159irozen\u00e9 zp\u016fsoben\u00e9 geodynamick\u00fdmi jevy Zem\u011b a tak\u00e9 um\u011ble vytvo\u0159en\u00e9 \u010dinnost\u00ed lid\u00ed. Seismologi\u00ed jsme se kr\u00e1tce zab\u00fdvali tak\u00e9 v p\u0159edchoz\u00edm \u010dl\u00e1nku\u00a0Geofyzika (kint.cz)<\/a><\/p>

Seismick\u00e9 vlny proch\u00e1z\u00ed zemsk\u00fdm t\u011blesem a vystupuj\u00ed zp\u011bt na povrch s informac\u00ed o fyzik\u00e1ln\u00edch vlastnostech vnitra Zem\u011b. Nev\u00fdhodou p\u0159irozen\u00fdch zem\u011bt\u0159esen\u00ed je, \u017ee nezn\u00e1me ani okam\u017eik ani m\u00edsto jejich vzniku. Tuto nev\u00fdhodu nemaj\u00ed podzemn\u00ed nukle\u00e1rn\u00ed v\u00fdbuchy\u00a0<\/em>4<\/a><\/sup>.<\/em><\/p>

Proto\u017ee rychlost seismick\u00fdch vln z\u00e1vis\u00ed mimo jin\u00e9 i na hustot\u011b, lze prov\u00e9st z\u00e1kladn\u00ed \u00favahy o rozlo\u017een\u00ed hustot v Zemi. Zem\u011b hustotn\u011b nehomogenn\u00ed s hustotami ve sv\u00e9m nitru vy\u0161\u0161\u00edmi ne\u017e 5,5 gcm-3<\/sup>. Dal\u0161\u00ed informaci o rozlo\u017een\u00ed hmot uvnit\u0159 Zem\u011b poskytuje moment setrva\u010dnosti.<\/p>

Bylo zji\u0161t\u011bno,\u00a0\u017ee moment setrva\u010dnosti Zem\u011b je 0,331 MR2<\/sup>\u00a0(kde M je hmota a R polom\u011br Zem\u011b), z \u010deho\u017e plyne, \u017ee hmota Zem\u011b je koncentrov\u00e1na v\u00edce kolem jej\u00edho st\u0159edu, i \u017ee hustoty ve st\u0159edu Zem\u011b jsou vy\u0161\u0161\u00ed ne\u017e pr\u016fm\u011brn\u00e9.<\/em><\/p>

Seismick\u00e9 paprsky proto mus\u00ed proch\u00e1zet Zem\u00ed po k\u0159iv\u00fdch drah\u00e1ch, odr\u00e1\u017eet se od r\u016fzn\u00fdch seismick\u00fdch rozhran\u00ed<\/em>.\u00a0Energie uvoln\u011bn\u00e1 p\u0159i zem\u011bt\u0159esen\u00ed nebo nukle\u00e1rn\u00edm v\u00fdbuchu se p\u0159em\u011bn\u00ed na r\u016fzn\u00e9 seismick\u00e9 vlny. Objemov\u00e9 pod\u00e9ln\u00e9 vlny P maj\u00ed dvojn\u00e1sobnou rychlost jako objemov\u00e9 vlny p\u0159\u00ed\u010dn\u00e9 i S. Na Zemi se v\u00fdznamn\u011b uplat\u0148uj\u00ed t\u00e9\u017e povrchov\u00e9 vlny L, kter\u00e9 jsou op\u011bt dvoj\u00edho druhu.<\/em><\/p>

Rayleighovy povrchov\u00e9 vlny jsou jakousi obdobou pod\u00e9ln\u00fdch vln, kde\u017eto Loveovy odpov\u00eddaj\u00ed p\u0159\u00ed\u010dn\u00fdm vln\u00e1m. Energie vln o velk\u00e9 d\u00e9lce pronik\u00e1 do v\u011bt\u0161\u00ed hloubky a rychleji ne\u017e vln o mal\u00e9 d\u00e9lce<\/em>\u00a05<\/a><\/sup>.<\/p>

Pr\u016fb\u011bh seismick\u00fdch paprsk\u016f Zem\u00ed je patrn\u00fd\u00a0<\/em>na dal\u0161\u00edm obr\u00e1zku, ukazuj\u00edc\u00edm t\u00e9\u017e Bullen\u016fv model Zem\u011b, maj\u00edc\u00edm t\u0159i hlavn\u00ed \u010d\u00e1sti: svrchn\u00ed pl\u00e1\u0161, pl\u00e1\u0161 a j\u00e1dro; ka\u017ed\u00e1 \u010d\u00e1st m\u00e1 sv\u00e9 dal\u0161\u00ed podrozd\u011blen\u00ed. Dnes se v\u00edce vyu\u017e\u00edv\u00e1 d\u011blen\u00ed pl\u00e1\u0161t\u011b na litosf\u00e9ru a astenosf\u00e9ru. Vrchn\u00ed \u010d\u00e1st litosf\u00e9ry tvo\u0159\u00ed zemsk\u00e1 k\u016fra\u00a0<\/em>6<\/a><\/sup>.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Pr\u016fchod P a S seismick\u00fdch vln zemsk\u00fdm t\u011blesem. Symbol c zna\u010d\u00ed odra\u017eenou P vlnu, I a K symboly popisuj\u00ed lomen\u00e9 P vlny na rozhran\u00edch j\u00e1dra a vn\u011bj\u0161\u00edho j\u00e1dra , zdroj: (Posp\u00ed\u0161il L.).<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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Seismick\u00e9 paprsky, vych\u00e1zej\u00edc\u00ed z ohniska, se do hloubky zak\u0159ivuj\u00ed. Paprsky S jsou zak\u0159iven\u011bj\u0161\u00ed ne\u017e P. Paprsky S, kon\u010d\u00ed \u2013 neproch\u00e1z\u00ed j\u00e1drem, resp. se od n\u011bj pouze odr\u00e1\u017eej\u00ed. J\u00e1dro se toti\u017e chov\u00e1 jako kapalina, co\u017e se projevuje t\u00edm, \u017ee nepropou\u0161t\u00ed S vlny<\/em>\u00a07<\/a><\/sup>.<\/p>

Nejv\u00fdrazn\u011bj\u0161\u00edm rozhran\u00edm je vn\u011bj\u0161\u00ed omezen\u00ed j\u00e1dra. Zemsk\u00e9 j\u00e1dro bylo objeveno Guttenbergem pomoc\u00ed pozorov\u00e1n\u00ed \u201eseismick\u00e9ho st\u00ednu\u201c. Kdyby nap\u0159. epicentrum zem\u011bt\u0159esen\u00ed le\u017eelo na z\u00e1pad, pak by P vlny mohly b\u00fdt registrov\u00e1ny na cel\u00e9 zem\u011bkouli s v\u00fdjimkou p\u00e1su na ji\u017en\u00ed polokouli mezi ji\u017e. zem. \u0161\u00ed\u0159kou 103\u00b0 a\u017e 142\u00b0, kde vlny P jsou velmi slab\u00e9.<\/em><\/p>

Je to zp\u016fsobeno t\u00edm, \u017ee P paprsek, kter\u00fd te\u010dn\u011b projde kolem j\u00e1dra, dopadne za 142\u00b0, kde\u017eto s n\u00edm bezprost\u0159edn\u011b sousedn\u00ed paprsek se ji\u017e zlom\u00ed do j\u00e1dra a vyjde na povrch ve st\u00ednov\u00e9 z\u00f3n\u011b<\/em>\u00a08<\/a><\/sup>.<\/p>

Studiem \u010das\u016f p\u0159\u00edchodu seismick\u00fdch vln, zejm\u00e9na nukle\u00e1rn\u00edch v\u00fdbuch\u016f, v r\u016fzn\u00fdch vzd\u00e1lenostech od epicentra mohly b\u00fdt konstruov\u00e1ny\u00a0hodochrony<\/strong>\u00a0a z jejich sklon\u016f zji\u0161t\u011bny z\u00e1vislosti rychlost\u00ed seismick\u00fdch vln na hloubce. V m\u00edstech, kde se rychlosti m\u011bn\u00ed skokem, le\u017e\u00ed hranice Bullenova modelu Zem\u011b<\/em>\u00a09<\/a><\/sup>\u00a0(viz obr\u00e1zek).<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Rychlost seismick\u00fdch vln v zemsk\u00e9m t\u011blese, dle 10<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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Bullen\u016fv model Zem byl vyu\u017eit t\u00e9\u017e pro v\u00fdpo\u010det dal\u0161\u00edch fyzik\u00e1ln\u00edch parametr\u016f: tlak, telpota (ve st\u0159edu zem\u011b 2.000 a\u017e 6.500 \u00b0C).<\/p>

Z hlediska struktur\u00e1ln\u00edho v\u00fdvoje Zem\u011b m\u00e1 nejv\u011bt\u0161\u00ed v\u00fdznam\u00a0litosf\u00e9ra (tj. zemsk\u00e1 k\u016fra a svrchn\u00ed pl\u00e1\u0161)<\/em><\/strong>. Rozhran\u00ed mezi nimi tvo\u0159\u00ed\u00a0Mohorovi\u010dicova diskontinuita<\/em><\/strong>\u00a0(MOHO), na n\u00ed\u017e se rychlost seismick\u00fdch vln skokem zv\u011bt\u0161uje.<\/p>

Zemsk\u00e1 k\u016fra<\/em><\/strong>\u00a0\u2013\u00a0m\u00e1 mocnost a slo\u017een\u00ed velmi rozd\u00edln\u00e9. Pod kontinenty se skl\u00e1d\u00e1 z vrstvy granitick\u00e9 a bazaltov\u00e9; rozhran\u00ed mezi nimi tvo\u0159\u00ed Conradova diskontinuita, jej\u00ed\u017e v\u00fdznam a prokazov\u00e1n\u00ed je nejednozna\u010dn\u00e9. Pr\u016fm\u011brn\u00e1 mocnost k\u016fry je 35 km.<\/em><\/p>

Pod oce\u00e1ny je pouze vrstva bazaltov\u00e1 a pr\u016fm\u011brn\u00e1 mocnost k\u016fry je jen 5 km. MOHO je hranic\u00ed, na n\u00ed\u017e se m\u011bn\u00ed chemick\u00e9 slo\u017een\u00ed hornin nebo jejich f\u00e1zov\u00fd stav, jejich hustota a rychlost seismick\u00fdch vln\u00a0<\/em>11<\/a><\/sup>.<\/p>

Svrchn\u00ed pl\u00e1\u0161 nen\u00ed v horizont\u00e1ln\u00edm sm\u011bru homogenn\u00ed (tj. sm\u011bry rychlost\u00ed\u00a0 Pn<\/sub>).\u00a0Av\u0161ak je\u0161t\u011b v\u00fdznamn\u011bj\u0161\u00ed zm\u011bny jsou ve sm\u011bru vertik\u00e1ln\u00edm, kde existuje\u00a0n\u00edzkorychlostn\u00ed vrstva<\/strong>. Podle n\u011bkter\u00fdch autor jsou do hloubky 700 km dokonce 4 n\u00edzkorychlostn\u00ed vrstvy.)<\/em>\u00a012<\/a><\/sup>.<\/p>

\u00a0Na z\u00e1klad v\u00fdzkum\u016f a dle v\u00fd\u0161e uveden\u00e9ho zdroje lze n\u00edzko rychlostn\u00ed vrstvu charakterizovat takto:<\/p>

  1. Le\u017e\u00ed v hloubce 60 \u2013 250 km a jej\u00ed hranice nen\u00ed ostr\u00e1.<\/em><\/li>
  2. Prob\u00edh\u00e1 kolem cel\u00e9 Zem\u011b.<\/em><\/li>
  3. Seismick\u00e9 vlny jsou pod oce\u00e1ny v\u00edce zpomalov\u00e1ny ne\u017e pod kontinenty. N\u00edzko rychlostn\u00ed vrstva le\u017e\u00ed toti\u017e pod oce\u00e1ny bl\u00ed\u017ee k zemsk\u00e9mu povrchu ne\u017e pod kontinenty. Dal\u0161\u00ed d\u016fkaz, \u017ee rozd\u00edly mezi oblast\u00ed oce\u00e1nickou a kontinent\u00e1ln\u00ed se neomezuj\u00ed pouze na zemskou k\u016fru do MOHO.<\/em><\/li>
  4. Vlny S krat\u0161\u00edch vlnov\u00fdch d\u00e9lek jsou pohlcov\u00e1ny. To znamen\u00e1, \u017ee horniny v n\u00edzko rychlostn\u00ed vrstv\u011b jsou ve stavu t\u00e9m\u011b\u0159 plastick\u00e9m, co\u017e z\u0159ejm\u011b sv\u011bd\u010d\u00ed o tom, \u017ee maj\u00ed teploty bl\u00edzk\u00e9 bodu t\u00e1n\u00ed.<\/em><\/li>
  5. Sopky jsou v\u011bt\u0161inou v m\u00edstech, kde jsou zem\u011bt\u0159esen\u00ed. Zem\u011bt\u0159esen\u00ed, kter\u00e1 souvisej\u00ed s vulkanismem, jsou z hloubek v\u011bt\u0161inou 60 \u2013 200 km. To znamen\u00e1, \u017ee vulkanick\u00e1 \u010dinnost je ve spojen\u00ed s poruchami v n\u00edzko rychlostn\u00ed vrstv\u011b, kter\u00e1 je z\u0159ejm\u011b zdrojem prim\u00e1rn\u00edho bazaltick\u00e9ho magmatu.<\/em><\/li>
  6. V\u011bt\u0161ina zem\u011bt\u0159esen\u00ed le\u017e\u00ed v\u0161ak do hloubky 60 km, nebo ve v\u011bt\u0161\u00edch hloubk\u00e1ch je materi\u00e1l ji\u017e v\u00edce plastick\u00fd, tak\u017ee anom\u00e1ln\u00ed nap\u011bt\u00ed se mohou z velk\u00e9 \u010d\u00e1sti vyrovn\u00e1vat \u201ete\u0159en\u00edm\u201c materi\u00e1lu.<\/em><\/li><\/ol>

    Zemskou k\u016fru a \u010d\u00e1st svrchn\u00edho pl\u00e1\u0161t\u011b a\u017e po n\u00edzko rychlostn\u00ed vrstvu souborn\u011b naz\u00fdvan\u00e9\u00a0litosf\u00e9ra<\/em><\/strong>\u00a0(lithos \u2013 \u0159ecky k\u00e1men), tvo\u0159\u00ed rigidn\u00ed horniny. Pod litosf\u00e9rou le\u017e\u00ed\u00a0astenosf\u00e9ra<\/em><\/strong>\u00a0(asthenos- \u0159ecky m\u011bkk\u00fd); je charakterizov\u00e1na plastick\u00fdmi horninami; pat\u0159\u00ed do n\u00ed cel\u00e1 n\u00edzko rychlostn\u00ed vrstva; doln\u00ed omezen\u00ed je podle r\u016fzn\u00fdch autor\u016f vcelmi rozd\u00edln\u00e9.<\/p>

    N\u00edzko rychlostn\u00ed vrstva<\/em><\/strong>\u00a0m\u00e1 z\u00e1sadn\u00ed v\u00fdznam pro v\u00fdklad izost\u00e1ze, tektoniky, horotvorn\u00fdch pochod\u016f, kontinent. drift, tektoniky litosf\u00e9rick\u00fdch blok (plate tectonics).<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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    Fyzik\u00e1ln\u00ed vlastnosti Zem\u011b<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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    Geodynamika se zab\u00fdv\u00e1 dal\u0161\u00edmi fyzik\u00e1ln\u00edmi vlastnostmi zem\u011b, zejm\u00e9na o n\u00e1sleduj\u00edc\u00ed:\u00a0rozlo\u017een\u00ed hustot<\/em><\/strong>\u00a0uvnit\u0159 Zem\u011b;\u00a0elastick\u00e9 vlastnosti<\/em><\/strong>\u00a0jako jsou\u00a0tlak<\/em><\/strong>\u00a0a\u00a0gravita\u010dn\u00ed zrychlen\u00ed<\/em><\/strong>\u00a0(lze odvodit z rychlost\u00ed seismick\u00fdch vln a hustotn\u00edho rozlo\u017een\u00ed uvnit\u0159 Zem\u011b); teploty v Zemi.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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    Teploty v Zemi<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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    Sou\u010dasn\u00fd tepeln\u00fd stav Zem\u011b vypl\u00fdv\u00e1 toti\u017e z jej\u00ed teplotn\u00ed historie, o n\u00ed\u017e byla vyslovena \u0159ada hypot\u00e9z, kter\u00e9 vych\u00e1zej\u00ed z ur\u010dit\u00fdch p\u0159edpoklad o vzniku a ran\u00e9 historii Zem\u011b, chemick\u00e9m slo\u017een\u00ed a fyzik\u00e1ln\u00edch vlastnostech hmoty, z n\u00ed\u017e se skl\u00e1d\u00e1 Zem\u011b<\/em>\u00a013<\/a><\/sup>.<\/p>

    Vztah mezi hloubkou a teplotou v Zemi vyjad\u0159uje\u00a0geoterma<\/em><\/strong>. Jako zdroje vnit\u0159n\u00edho tepla se p\u0159edpokl\u00e1daj\u00ed:<\/p>

    gravita\u010dn\u00ed energie, kter\u00e1 se p\u0159em\u011bnila v teplo p\u0159i formov\u00e1n\u00ed zemsk\u00e9ho j\u00e1dra,<\/p>

    energie vznikl\u00e1 t\u0159en\u00edm p\u0159i zemsk\u00fdch slapech nebo subdukci se m\u011bn\u00ed v energii tepelnou a to pravd\u011bpodobn\u011b v oslaben\u00fdch z\u00f3n\u00e1ch, jako je nap\u0159. N\u00edzko rychlostn\u00ed vrstva, subduk\u010dn\u00ed z\u00f3ny,<\/p>

    tepeln\u00e1 energie vznikl\u00e1 p\u0159i rozpadu radioaktivn\u00edch prvk\u016f. Je to patrn\u011b hlavn\u00ed zdroj, udr\u017euj\u00edc\u00ed vn\u011bj\u0161\u00ed tepeln\u00fd stav Zem\u011b a sou\u010dasn\u00fd tepeln\u00fd tok:<\/p>

    \u2013\u00a0tepeln\u00fd tok z nitra Zem\u011b<\/em><\/strong>\u00a0(veden\u00ed, s\u00e1l\u00e1n\u00ed, konvekce); jeho hloubkov\u00e9 m\u011b\u0159en\u00ed,<\/p>

    \u2013\u00a0hloubkov\u00e9 teplotn\u00ed pom\u011bry<\/em><\/strong>\u00a0(tepeln\u00e1 vodivost k(z), rozd\u011blen\u00ed tepeln\u00fdch zdroj\u016f A(z),<\/p>

    \u2013\u00a0teploty povrchu Zem\u011b<\/em><\/strong>\u00a0viz obr\u00e1zky,<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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    Geodynamika \u2013 teplota Zem\u011b (1), zdroj (Posp\u00ed\u0161il, L.)<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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    Geodynamika \u2013 teplota Zem\u011b (2), zdroj (Posp\u00ed\u0161il, L.)<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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    \u2013\u00a0viskozita<\/em><\/strong>\u00a0jednotliv\u00fdch vrstev Zem\u011b je zn\u00e1m\u00e1 jen velmi p\u0159ibli\u017en\u011b; pro n\u00e1s je zejm\u00e9na zaj\u00edmav\u00e9, \u017ee \u0159ada pozorov\u00e1n\u00ed sv\u011bd\u010d\u00ed o tom, \u017ee ve svrchn\u00edm pl\u00e1\u0161ti existuje n\u00edzkoviskozn\u00ed vrstva v hloubk\u00e1ch odpov\u00eddaj\u00edc\u00edch n\u00edzkorychlostn\u00ed vrstv\u011b\u00a0<\/em>14<\/a><\/sup>,<\/em><\/p>

    \u2013\u00a0\u00a0 zemsk\u00e9 magnetick\u00e9 pole \u2013<\/strong><\/em>\u00a0silo\u010d\u00e1ry magnetick\u00e9ho pole maj\u00ed vertik\u00e1ln\u00ed sm\u011br v magnetick\u00fdch p\u00f3lech jejich\u017e poloha se s \u010dasem m\u011bn\u00ed (v sou\u010dasnosti v severn\u00ed Kanad\u011b a na Antarktid\u011b, jejich spojnice neproch\u00e1z\u00ed st\u0159edem Zem\u011b);<\/p>

    p\u0159\u00ed\u010dina pole je z 94 % uvnit\u0159 Zem\u011b, zbytek vyd\u00e1vaj\u00ed vn\u011bj\u0161\u00ed zdroje; pole lze vyj\u00e1d\u0159it jako \u00fa\u010dinek \u0159ady magnetick\u00fdch dip\u00f3l\u016f ve st\u0159edu Zem\u011b, maj\u00edc\u00edch r\u016fznou orientaci;<\/p>

    prvn\u00ed z t\u011bchto dip\u00f3l reprezentuje podstatnou \u010d\u00e1st pravideln\u00e9ho pole Zem\u011b, je to tzv.\u00a0sklon\u011bn\u00fd geocentrick\u00fd dip\u00f3l<\/em><\/strong>, jeho\u017e osa sv\u00edr\u00e1 s osou zemsk\u00e9 rotace \u00fahel 11,5\u00b0 a prot\u00edn\u00e1 Zemi v geomagnetick\u00fdch p\u00f3lech;<\/p>

    kr\u00e1tkodob\u00e9 periodick\u00e9 variace magnetick\u00e9ho pole<\/em><\/strong>\u00a0(\u0159\u00e1dov\u011b hodin, dn\u016f i rok\u016f) mohou b\u00fdt vysv\u011btleny pomoc\u00ed elektrick\u00fdch proud\u016f v pl\u00e1\u0161ti a ionosf\u00e9\u0159e; zm\u011bny v intenzit\u011b dosahuj\u00ed \u0159\u00e1dov\u011b 10 a\u017e 100 nT,<\/p>

    \u2013 \u00a0 magnetick\u00e9 bou\u0159e\u00a0<\/em><\/strong>\u2013 jsou kr\u00e1tkodob\u00e9, nepravideln\u00e9 fluktuace, kter\u00e9 Mohou p\u0159es\u00e1hnout hodnotu 103<\/sup>\u00a0nT; vznikaj\u00ed v ionosf\u00e9\u0159e vlivem anom\u00e1ln\u00edho bombardov\u00e1n\u00ed slune\u010dn\u00edm z\u00e1\u0159en\u00edm, hlavn\u011b p\u0159i v\u00fdskytu slune\u010dn\u00edch skvrn<\/em>\u00a015<\/a><\/sup>, viz obr\u00e1zek,<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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    Magnetick\u00e1 bou\u0159e, zdroj (Posp\u00ed\u0161il, L.)<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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    \u2013 \u00a0\u00a0sekul\u00e1rn\u00ed zm\u011bny<\/strong>\u00a0se projevuj\u00ed v deklinaci, inklinaci i v intenzit. Sekul\u00e1rn\u00ed variace v intenzit maj\u00ed hodnoty jednotky a\u017e des\u00edtky nT za rok (mapy izopor); cyklick\u00e9 zm\u011bny ve sm\u011bru pole maj\u00ed periodu n\u011bkolik set let a od pr\u016fm\u011brn\u00e9ho sm\u011bru vyvol\u00e1vaj\u00ed odchylky 10 a\u017e 20 \u00b0 na ob\u011b strany,<\/em><\/p>

    \u2013\u00a0\u00a0\u00a0magnetick\u00fd moment Zem\u011b<\/strong>\u00a0se sekul\u00e1rn\u011b m\u011bn\u00ed; za 100 let se zmen\u0161il o 5%; zd\u00e1 se v\u0161ak sp\u00ed\u0161e, \u017ee velikost momentu osciluje kolem ur\u010dit\u00e9 hodnoty,<\/em><\/p>

    \u2013\u00a0\u00a0\u00a0paleomagnetismus<\/strong>\u00a0studuje fosiln\u00ed i remanentn\u00ed magnetismus; putov\u00e1n\u00ed p\u00f3l\u016f, magnetick\u00e9 inverze v korelaci s line\u00e1rn\u00edmi magnetick\u00fdmi anom\u00e1liemi pat\u0159\u00ed mezi nejd\u016fle\u017eit\u011bj\u0161\u00ed d\u016fkazy pro kontinent\u00e1ln\u00ed drift,<\/em><\/p>

    \u2013\u00a0\u00a0\u00a0Zemsk\u00e9 t\u00edhov\u00e9 pole<\/strong>\u00a0\u2013 hmoty Zem\u011b vyvol\u00e1vaj\u00ed gravita\u010dn\u00ed zrychlen\u00ed, rotace odst\u0159ediv\u00e9 zrychlen\u00ed; vektorov\u00fd sou\u010det obou zrychlen\u00ed ozna\u010dujeme jako t\u00edhov\u00e9 zrychlen\u00ed i t\u00ed\u017ee; Zemsk\u00e1 rotace zp\u016fsobila \u017ee Zem\u011b je na p\u00f3lech zplo\u0161t\u011bl\u00e1; t\u00edhov\u00e9 zrychlen\u00ed je funkc\u00ed zem pisn\u00e9 \u0161\u00ed\u0159ky \u2013 na p\u00f3lech je nejv\u011bt\u0161\u00ed, na rovn\u00edku nejmen\u0161\u00ed;<\/em><\/p>

    \u2013\u00a0\u00a0\u00a0t\u00edhov\u00e9 anom\u00e1lie<\/strong><\/em>\u00a0\u2013 z voln\u00e9ho vzduchu (nadbytky, resp. nedostatky hmoty uvnit\u0159 Zem\u011b ve srovn\u00e1n\u00ed s norm\u00e1ln\u00edm rozlo\u017een\u00edm hmot, kter\u00e9 odpov\u00edd\u00e1 norm\u00e1ln\u00ed t\u00ed\u017ei);<\/p>

    \u00dapln\u00e9 Bouguerovy anom\u00e1lie vyjad\u0159uj\u00ed \u00fa\u010dinek hmot s anom\u00e1ln\u00ed hustotou (tj. hustotou rozd\u00edlnou od pr\u016fm\u011brn\u00e9);<\/p>

    tyto hmoty le\u017e\u00ed hlavn\u011b ve vrchn\u00ed \u010d\u00e1sti lirosf\u00e9ry \u2013 bylo zji\u0161t\u011bno, \u017ee \u00fapln\u00e9 Bouguerovy anom\u00e1lie jsou z\u00e1porn\u00e9 ve vysok\u00fdch oblastech, naproti tomu v prostor\u00e1ch oce\u00e1n jsou kladn\u00e9;<\/p>

    izostatick\u00e9 anom\u00e1lie \u2013 nulov\u00e1 anom\u00e1lie zna\u010d\u00ed, \u017ee blok je v hydrostatick\u00e9 rovnov\u00e1ze, z\u00e1porn\u00e1 anom\u00e1lie zna\u010d\u00ed, \u017ee blok m\u00e1 p\u0159\u00edli\u0161 hlubok\u00e9 ko\u0159eny (Airy) nebo p\u0159\u00edli\u0161 n\u00edzkou pr\u016fm\u011brnou hustotu (blok je hydrostaticky tla\u010den nahoru a nep\u016fsob\u00ed-li dal\u0161\u00ed v\u011bt\u0161\u00ed s\u00edly v opa\u010dn\u00e9m sm\u011bru, pak blok stoup\u00e1), kladn\u00e9 izostatick\u00e9 anom\u00e1lie naopak vyjad\u0159uj\u00ed tendenci klesat.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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    Geologick\u00fd cyklus a st\u00e1\u0159\u00ed hornin<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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    Jsou dva zdroje energie, kter\u00e9 uv\u00e1d\u011bj\u00ed do \u010dinnosti geologick\u00e9 pochody: vnit\u0159n\u00ed teplo Zem\u011b a slune\u010dn\u00ed z\u00e1\u0159en\u00ed. Vnit\u0159n\u00ed zdroj dod\u00e1v\u00e1 energii pro vznik vyv\u0159el\u00fdch hornin, metamorfn\u00ed a tektonick\u00e9 pochody. Vn\u011bj\u0161\u00ed zdroj (Slunce) uv\u00e1d\u00ed do kolob\u011bhu atmosf\u00e9ru a hydrosf\u00e9ru, v\u011btr\u00e1n\u00ed, erozi a tvorbu sediment\u00e1rn\u00edch hornin. D\u016fle\u017eitou roli d\u00e1le hraj\u00ed geochemick\u00e9 pochody.<\/em><\/p>

    Vz\u00e1jemnou vazbu v\u0161ech proces vyjad\u0159uje geologick\u00fd cyklus (Obr\u00e1zek 32), kter\u00fd nen\u00ed uzav\u0159en\u00fd. Magma, kter\u00e9 vznik\u00e1 v pl\u00e1\u0161ti v hloubce kolem 50 km a v\u00edce, vystupuje k povrchu, \u010d\u00edm\u017e se obohacuje o dal\u0161\u00ed materi\u00e1l obsahuj\u00edc\u00ed silik\u00e1ty, co\u017e umo\u017e\u0148uje vznik nov\u00fdch hornin v zemsk\u00e9 k\u016f\u0159e.<\/em><\/p>

    Sou\u010dasn\u011b se uvol\u0148uje voda a dal\u0161\u00ed plynn\u00e9 sou\u010d\u00e1sti. Z toho lze vyvozovat, \u017ee zemsk\u00e1 k\u016fra, hydrosf\u00e9ra a atmosf\u00e9ra se tvo\u0159ily postupn\u011b jako d\u016fsledek opakov\u00e1n\u00ed magmatick\u00e9 \u010dinnosti<\/em>.\u00a0<\/em>16<\/a><\/sup><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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    Geologick\u00fd cyklus st\u00e1\u0159\u00ed hornin, zdroj (Posp\u00ed\u0161il, L.)<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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    St\u00e1\u0159\u00ed hornin<\/em><\/strong>\u00a0ur\u010dujeme bu paleontologick\u00fdmi metodami podle zkamen\u011blin nebo radioaktivn\u00edmi metodami a nejnov\u011bji i s pou\u017eit\u00edm paleomagnetismu.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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    Litosf\u00e9ra<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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    Reologick\u00e9 chov\u00e1n\u00ed litosf\u00e9ry a astenosf\u00e9ry je pops\u00e1no viskozitou a z\u00e1konem \u00fabytku deformace s \u010dasem. Kapalina oh\u0159\u00edvan\u00e1 zevnit\u0159 nebo zespoda vykon\u00e1v\u00e1 konvek\u010dn\u00ed pohyb, jestli\u017ee Rayleighovo \u010d\u00edslo p\u0159ekro\u010d\u00ed kritickou mez<\/em>.<\/p>

    Rayleighovo \u010d\u00edslo pro pl\u00e1\u0161 je podstatn\u011b v\u011bt\u0161\u00ed ne\u017e kritick\u00e1 hranice pro spu\u0161t\u011bn\u00ed konvekce. Pro term\u00e1ln\u00ed konvekci s velmi vysok\u00fdm Rayleighov\u00fdm \u010d\u00edslem je charakteristick\u00e1 existence tenk\u00e9 term\u00e1ln\u00ed vrstvy, kterou je litosf\u00e9ra.<\/em><\/p>

    Z toho hlediska je litosf\u00e9ra term\u00e1ln\u00ed dif\u00fazn\u00ed vrstvou syst\u00e9mu pl\u00e1\u0161\u0165ov\u00e9 konvekce. To znamen\u00e1, \u017ee je m\u00e1lo stabiln\u00ed a rozd\u011blen\u00ed teploty je ur\u010dov\u00e1no veden\u00edm tepla, zat\u00edmco v pl\u00e1\u0161ti jsou teploty bl\u00edzk\u00e9 adiabatick\u00fdm teplot\u00e1m.<\/em>\u00a017<\/a><\/sup><\/p>

    U litosf\u00e9ry sledujeme p\u0159edev\u0161\u00edm jej\u00ed vertik\u00e1ln\u00ed a horizont\u00e1ln\u00ed pohyby, rozp\u00edn\u00e1n\u00ed mo\u0159sk\u00e9ho dna (spreading), st\u0159edooce\u00e1nsk\u00e9 h\u0159bety a rifty, konvekce a rotace, konvekce v pl\u00e1\u0161ti a gravita\u010dn\u00ed pole (tektonickou aktivitu), MOHO vz. Zemskou k\u016fru, rozhran\u00ed litosf\u00e9ry a astenosf\u00e9ry. Uveden\u00e9 oblasti jsou bl\u00ed\u017ee popsan\u00e9 v pr\u00e1ci\u00a018<\/a><\/sup>.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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    Kontinent\u00e1ln\u00ed drift\n<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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    Paleomagnetismus p\u0159in\u00e1\u0161\u00ed \u00fadaje o driftu.\u00a0Vhodn\u011b vybran\u00e9 vzorky hornin r\u016fzn\u00e9ho st\u00e1\u0159\u00ed ukazuj\u00ed, \u017ee sm\u011br jejich remanentn\u00ed magnetizace je jin\u00fd, ne\u017e kdyby byly namagnetov\u00e1ny v dne\u0161n\u00edm magnetick\u00e9m poli Zem\u011b<\/em>.<\/p>

    Ze sm\u011bru vektoru remanentn\u00ed magnetizace lze t\u00e9\u017e ur\u010dit sm\u011br ke geomagnetick\u00e9mu p\u00f3lu. Z dan\u00fdch \u00fadaj lze tedy rekonstruovat polohy paleop\u00f3l pro jednotliv\u00e1 geologick\u00e1 obdob\u00ed vzhledem k dne\u0161n\u00ed geografick\u00e9 s\u00edti. Posun p\u00f3l\u016f m\u016f\u017ee b\u00fdt zp\u016fsoben<\/em>:<\/p>

    \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a01. Pohybem \u010d\u00e1st\u00ed nebo cel\u00e9 zemsk\u00e9 k\u016fry v i nem\u011bnn\u00e9 poloze magnetick\u00e9ho p\u00f3lu (pop\u0159. nem\u011bnn\u00e9 ose rotace Zem\u011b.<\/em><\/p>

    \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 2. P\u0159em\u00eds\u0165ov\u00e1n\u00edm magnetick\u00e9ho p\u00f3lu vzhledem k nem\u011bnn\u00e9 poloze zemsk\u00e9 k\u016fry.<\/em><\/p>

    V sou\u010dasn\u00e9 dob\u011b se \u010dast\u011bji zobrazuj\u00ed v\u00fdsledky paleomagnetick\u00fdch m\u011b\u0159en\u00ed tak, \u017ee do sou\u010dasn\u00e9 grafick\u00e9 s\u00edt s kontinenty zakreslujeme paleomagnetick\u00e9 p\u00f3ly, kter\u00e9 spojujeme plynulou \u010darou, aby bylo vid\u011bt jak se jejich poloha m\u011bnila.<\/em>19<\/a><\/sup><\/p>

    Na obr\u00e1zku jsou zobrazeny paleomagnetick\u00e9 vektory k\u0159\u00eddov\u00fdch a\u017e miocenn\u00edch hornin v prostoru Karpat.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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    Wegennerem proveden\u00e1 rekonstrukce kontinent\u016f a sou\u010dasn\u00e9 rozlo\u017een\u00ed hlavn\u00edch litosf\u00e9rick\u00fdch desek. N\u00e1lezy paleozoick\u00fdch a\u017e triasov\u00fdch zkamen\u011blin (C a\u017e H).J\u00e1dro Gondwany a Laurasie tvo\u0159\u00ed horniny star\u0161\u00ed ne\u017e 1700mil. let (H); Sm\u011bry pohyb\u016f ledovc\u016f, paleomagnetick\u00fd p\u00f3l a hranice zaledn\u011bn\u00ed ve svrchn\u00edm karbonu (I). zdroj (Posp\u00ed\u0161il, L.)<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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    Tektonika litosf\u00e9rick\u00fdch desek<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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    Teorie kontinent\u00e1ln\u00edho driftu a rozp\u00edn\u00e1n\u00ed mo\u0159sk\u00e9ho dna byly z\u00e1kladn\u00edmi kameny pro koncepci tektoniky litosf\u00e9rick\u00fdch desek (plate tektonics), kter\u00e1 je novou glob\u00e1ln\u00ed tektonikou.<\/em><\/p>

    Tato teorie p\u0159edpokl\u00e1d\u00e1, \u017ee povrchov\u00e1 \u010d\u00e1st Zem\u011b se skl\u00e1d\u00e1 z n\u011bkolika rigidn\u00edch blok\u016f, kter\u00e9 jsou ve vz\u00e1jemn\u00e9m relativn\u00edm pohybu\u00a0<\/em>(viz obr\u00e1zek).\u00a0Bloky sahaj\u00ed do hloubky kolem 100 km a klouzaj\u00ed po astenosf\u00e9\u0159e<\/em>.\u00a020<\/a><\/sup>.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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    Tektonika litosf\u00e9rick\u00fdch desek, zdroj (Posp\u00ed\u0161il, L.)<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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    Hranice litosf\u00e9rick\u00fdch desek byly stanoveny podle p\u00e1s\u016f\u00a0zv\u00fd\u0161en\u00e9 seismicity<\/strong>. Existuj\u00ed t\u0159i z\u00e1kladn\u00ed typy hranic a) Extenz\u00edvn\u00ed (divergentn\u00ed) hranice, na kter\u00e9 norm\u00e1lov\u00e9 slo\u017eky sil p\u016fsob\u00edc\u00edch na desky m\u00ed\u0159\u00ed sm\u011brem od hranice, b) Kompresn\u00ed (konvergentn\u00ed) \u2013 norm\u00e1lov\u00e9 slo\u017eky sil sm\u011b\u0159uj\u00ed ke hranici. Pod\u00e9l extenz\u00edvn\u00ed hranice se symetricky na ob strany vytv\u00e1\u0159\u00ed nov\u00e1 oce\u00e1nsk\u00e1 litosf\u00e9ra, zat\u00edmco pod\u00e9l konvergentn\u00edch hranic se litosf\u00e9ra asymetricky pon\u00e1\u0159\u00ed do pl\u00e1\u0161t\u011b (subdukce).<\/em><\/p>

    Tento typ hranice b\u00fdv\u00e1 doprov\u00e1zen oce\u00e1nsk\u00fdmi p\u0159\u00edkopy, vznikem ostrovn\u00edch oblouk a tektonickou aktivitou okraje kontinent (nap\u0159. alpinsko-himal\u00e1jsk\u00fd horsk\u00fd p\u00e1s). c) T\u0159et\u00edm typem hranice jsou transformn\u00ed zlomy. Jejich objev je jedn\u00edm z d\u016fle\u017eit\u00fdch v\u00fdsledk\u016f v\u00fdzkumu magnetick\u00fdch anom\u00e1li\u00ed v severov\u00fdchodn\u00ed \u010d\u00e1sti Tich\u00e9ho oce\u00e1nu. Interpretaci podal J. T. Wilson; vymezil 10 typ transformn\u00edch zlom\u016f<\/em>.\u00a021<\/a><\/sup>.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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    Ve vztahu k bezpe\u010dnosti<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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    Geodynamika poskytuje ve vztahu k bezpe\u010dnosti mnoho d\u016fle\u017eit\u00fdch informac\u00ed, proto\u017ee n\u00e1vrh a konstrukce bezpe\u010dnostn\u011b kritick\u00fdch objekt\u016f, syst\u00e9m\u016f, prvk\u016f apod. vych\u00e1z\u00ed z jist\u00fdch zad\u00e1vac\u00edch podm\u00ednek zohled\u0148uj\u00edc\u00ed okoln\u00ed provozn\u00ed podm\u00ednky v dan\u00e9m \u010dase. Uveden\u00e9 provozn\u00ed podm\u00ednky se \u010dasem m\u011bn\u00ed a co v\u00edc, ob\u010das nast\u00e1vaj\u00ed jevy, kter\u00e9 dan\u00e9 n\u00e1vrhov\u00e9 limity objekt\u016f v\u00fdrazn\u011b p\u0159ekra\u010duj\u00ed (geomagnetick\u00e9 bou\u0159e, zem\u011bt\u0159esen\u00ed, nestabiln\u00ed podlo\u017e\u00ed staveb, ztekucen\u00ed podlo\u017e\u00ed, v\u00fdv\u011br plyn\u016f ze zem\u011b, sope\u010dn\u00e9 \u010dinnosti \u2013 prach, z\u00e1plavy zp\u016fsoben\u00e9 geodynamick\u00fdmi jevy Zem\u011b apod.). Geodynamika n\u00e1m pom\u00e1h\u00e1 t\u011bmto ud\u00e1lostem porozum\u011bt a zva\u017eovat jejich ohro\u017een\u00ed a rizika.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"

    Geodynamika Zem\u011b Z\u00e1klady stavby zemsk\u00e9ho t\u011blesa a Geodynamika Geodynamika se zab\u00fdv\u00e1 v\u00fdzkumem planet a jejich v\u00fdvoji. Je sou\u010d\u00e1st\u00ed n\u011bkolika v\u011bdn\u00edch […]<\/p>\n","protected":false},"author":1,"featured_media":1327,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[184],"tags":[95,105,107],"class_list":["post-1326","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-fyzika-a-bezpecnost","tag-bezpecnost","tag-fyzika","tag-geodynamika"],"_links":{"self":[{"href":"https:\/\/test.kint.cz\/sk\/wp-json\/wp\/v2\/posts\/1326","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/test.kint.cz\/sk\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/test.kint.cz\/sk\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/test.kint.cz\/sk\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/test.kint.cz\/sk\/wp-json\/wp\/v2\/comments?post=1326"}],"version-history":[{"count":16,"href":"https:\/\/test.kint.cz\/sk\/wp-json\/wp\/v2\/posts\/1326\/revisions"}],"predecessor-version":[{"id":3769,"href":"https:\/\/test.kint.cz\/sk\/wp-json\/wp\/v2\/posts\/1326\/revisions\/3769"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/test.kint.cz\/sk\/wp-json\/wp\/v2\/media\/1327"}],"wp:attachment":[{"href":"https:\/\/test.kint.cz\/sk\/wp-json\/wp\/v2\/media?parent=1326"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/test.kint.cz\/sk\/wp-json\/wp\/v2\/categories?post=1326"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/test.kint.cz\/sk\/wp-json\/wp\/v2\/tags?post=1326"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}