Izimiso Eziyisisekelo Zefiziksi Yomhlaba ku-Geophysics
I-Geophysics iyigatsha lesayensi yomhlaba elifunda uMhlaba kusetshenziswa izimiso ze-physics. Nakuba i-geology incike kakhulu ekubonweni kwamatshe nezakhiwo ebusweni, i-geophysics "ibona" uMhlaba ngokungaqondile ngezimpendulo ezibonakalayo: amagagasi, amasimu adonsela phansi, amandla kazibuthe, ugesi, ukushisa, kanye nemisebe. Ngamanye amazwi, i-geophysics ifuna ukuphendula imibuzo efana nokuthi kwenzekani ngaphansi kobuso, ukuthi yiziphi izakhiwo zezinto zayo, nokuthi yiziphi izinqubo ezenzekayo—ngaphandle kokumba noma ukumba yonke indawo.
Ukuze siqinisekise ukuqonda okuqinile kwe-geophysics, sidinga ukubukeza izimiso ze-Earth physics ezisekela izindlela ze-geophysical. Lezi zimiso zifaka phakathi imiqondo ye-elastic media, ukusabalala kwamagagasi, amasimu angase abe khona, ukungeniswa kwe-electromagnetic, ukudluliselwa kokushisa, kanye nobudlelwano phakathi kwezakhiwo ezibonakalayo zezinto kanye nezimo ze-geological.
1. Umhlaba njengohlelo olubonakalayo: ukwakheka, isakhiwo, kanye nezakhiwo zezinto ezibonakalayo
Ngokwemvelo, uMhlaba ungacatshangwa njengohlelo olunezingqimba: uqweqwe, i-mantle, i-outer core ewuketshezi, kanye ne-solid inner core. Lokhu kuhlukaniswa okunezingqimba akuzona nje izingqimba ze-geological, kodwa futhi kubonisa izakhiwo zomzimba ezifana nobuningi, ukuguquguquka, ukuhanjiswa kukagesi, izinga lokushisa, kanye ne-magnetism. Ku-geophysics, lezi zakhiwo zomzimba ziyi-"parameter" eyinhloko.
Izinto ezahlukene zisabela ngendlela ehlukile emandleni nasemandleni. Isibonelo, amatshe aminyene agcwele i-igneous avame ukuba nobuningi obukhulu kunezihlabathi ezikhululekile; amatshe agcwele amanzi ahambisa kakhulu ugesi kunamatshe omile; kanti amaminerali anamandla afana ne-magnetite anika amatshe amandla aphezulu okusebenzisa amandla kagesi. Lokhu kwehluka ekuphenduleni kuveza ukungalingani okulinganiselwe.
2. Insimu yamandla adonsela phansi kanye nomqondo wensimu engaba khona
Esinye sezimiso eziyisisekelo zefiziksi yoMhlaba amandla adonsela phansi. Insimu yamandla adonsela phansi yoMhlaba ayifani ngenxa yokusatshalaliswa kobukhulu obungafani. Amatshe anamandla aphezulu "azodonsa" ngamandla amakhulu kunamatshe angenamandla kangako. I-geophysics yamandla adonsela phansi isebenzisa ukuhlukahluka okuncane ekusheshiseni amandla adonsela phansi (ukungalingani kwamandla adonsela phansi) ukuze kuchazwe izakhiwo ezingaphansi komhlaba.
Ngokwezibalo, amandla adonsela phansi yinsimu engaba khona, okungukuthi, insimu engatholakala emsebenzini ongaba khona futhi ihlangabezane nesibalo se-Laplace/Poisson ngaphansi kwezimo ezithile. Lokhu kubalulekile ngoba izindlela eziningi ze-geophysical—amandla adonsela phansi kanye ne-magnetic—zinezici ezingavamile: iphethini eyodwa engavamile ingabangelwa ukuhlelwa okuhlukahlukene kwe-subsurface. Ngakho-ke, ukuhumusha kudinga imikhawulo eyengeziwe njengedatha ye-geological, idatha ye-seismic, noma ulwazi lokubhoboza.
Ukusetshenziswa kwayo okusebenzayo kufaka phakathi ukumaka izitsha ze-sedimentary, ukuhlonza ama-salt domes, kanye nokufunda i-isostasy (ibhalansi yesisindo se-lithosphere maqondana ne-mantle). Isimiso se-isostasy sichaza ukuthi kungani izintaba zinezimpande ezikhanyayo noma ezijiyile, ezizivumela ukuthi zintante uma kuqhathaniswa ne-mantle.
3. Amandla kazibuthe oMhlaba: amasimu kazibuthe kanye nemithombo yezimo ezingavamile zikamazibuthe
Umhlaba unensimu yamagnetic eyinhloko etholakala ekushintsheni kwengaphakathi lawo langaphandle eliwuketshezi (i-geodynamo). Ngaphezu kwensimu eyinhloko, kunezindawo zamagnetic zendawo ezivela emadwaleni anamandla. I-geophysics yamagnetic ilinganisa ukuhlukahluka kwensimu yamagnetic ukuze idwebe izakhiwo ze-geological, ikakhulukazi lezo ezihlotshaniswa namadwala angcolile kanye nama-metamorphic acebile ngamaminerali anamandla.
Isimiso esiyinhloko lapha ukuthi ukugqwala kwamatshe kuqukethe izingxenye ezimbili: ukugqwala okubangelwa amandla (okuqhathaniswa nensimu yamanje yamagnetic yoMhlaba) kanye nokugqwala okuhlala njalo (insalela yokugqwala okudlule, lapho idwala lakhiwa). Ukugqwala okuhlala njalo kuwusizo kakhulu ku-paleomagnetism ekwakheni kabusha ukunyakaza kwamapuleti e-tectonic kanye nomlando wokuguqulwa kwe-magnetic pole yoMhlaba.
Ngokwezinga lesifunda, idatha yamagnetic isiza ukumaka isisekelo (umhlabathi) ngaphansi kwezingqimba ezijiyile, ukulandelela amaphutha, nokuhlola amaminerali.
4. Amagagasi okuzamazama komhlaba kanye nokunwebeka kwe-medium
Isimiso esiyinhloko se-physical ku-geophysics yi-wave mechanics kuma-elastic media. Izindlela ze-Seismic zisebenzisa amaza e-elastic asakazeka eMhlabeni. Kunezinhlobo ezimbili eziyinhloko zamaza ngaphakathi koMhlaba: ama-P-wave (ayinhloko, ama-longitudinal) kanye nama-S-wave (awesibili, anqamulayo). Ama-P-wave angasakazeka ezintweni eziqinile kanye noketshezi, kuyilapho ama-S-wave engenakusakazeka oketshezini. Leli qiniso elibonakalayo liyisizathu esibalulekile sokuthi kungani sazi ukuthi ingaphakathi loMhlaba liwuketshezi: ama-S-wave awakwazi ukudlula kuwo.
Ijubane legagasi lokuzamazama komhlaba linqunywa yi-moduli enwebekayo kanye nobuningi bezinto ezibonakalayo. Kalula nje, amatshe aqinile futhi aminyene avame ukuba nesivinini esiphezulu samagagasi. Lapho amagagasi edlula ezingqimbeni ezinezakhiwo ezahlukene, ukubonakaliswa kanye nokugqama kwenzeka, kulandela izimiso ezifana nomthetho kaSnell kuma-optics. Kusukela esikhathini sokuhamba kwamagagasi, ubukhulu, kanye nesimo samagagasi, izazi ze-geophysicists zingalinganisa ukujula kwengqimba, ukujiya kwenhlabathi, kanye nokuba khona koketshezi.
I-seismology yomhlaba wonke ihlola ukuzamazama komhlaba ukuze idwebe isakhiwo se-mantle kanye ne-core, kuyilapho i-seismology yokuhlola idweba ama-oyili, igesi, kanye namachibi angaphansi komhlaba ngezinga lendawo.
5. Ugesi kanye ne-electromagnetism: ukuhanjiswa kwamandla, ukumelana namandla, kanye nokungeniswa kwamandla
Izinqubo eziningi ezingaphansi komhlaba zihilela uketshezi, ukwakheka kwamaminerali, kanye nokwehluka kwezinga lokushisa—konke okuthinta ukuhanjiswa kukagesi. Isimiso esiyisisekelo sezindlela zikagesi neze-electromagnetic ubuhlobo phakathi kogesi wamanje, insimu kagesi, kanye nezakhiwo ze-medium, ezivame ukufingqwa ngumthetho ka-Ohm ngesimo esiqhubekayo (J = σE), kanti i-σ iyi-conductivity.
Ukumelana, ukuvuleka okubangelwa yi-polarization (IP), i-magnetotelluric (MT), kanye nezinye izindlela ze-electromagnetic zilinganisa impendulo ye-subsurface emithonjeni yamanje/yensimu, kokubili yokwenziwa kanye nemvelo. Isimiso sokungeniswa kwe-electromagnetic—esakhiwe emthethweni kaFaraday—sichaza ukuthi ukushintsha amasimu kazibuthe kukhiqiza kanjani amasimu kagesi kanye nemisinga ye-eddy enhlabathini. Lawa masimu e-eddy abe esekhiqiza amasimu kazibuthe esibili alinganiswa ebusweni.
Izinto ezigcwele amanzi anosawoti zinamandla okuhambisa amanzi kakhulu; ubumba luvame ukudlulisa amanzi ngenxa yezindlela zokuhambisa amanzi ebusweni. Ngokuphambene nalokho, amatshe ekristalu owomile kanye nama-hydrocarbon avame ukumelana. Ngakho-ke, izindlela ze-EM zisetshenziswa kabanzi emanzini angaphansi komhlaba, ekuhlolweni kwe-geothermal, ekuhlolweni kwamaminerali e-sulfide, kanye nasekufundweni kwezindawo zamaphutha ezigcwele uketshezi.
6. Ukudluliselwa kwe-Geothermal kanye nokushisa: ukuqhutshwa kanye nokudluliselwa kwe-convection
Umhlaba awumile; ugeleza amandla okushisa esuka ngaphakathi aye phezulu. Izimiso zokudluliselwa kokushisa zifaka phakathi ukuqhutshwa komoya (ukugeleza kokushisa ngokusebenzisa izinto ngaphandle kokudluliselwa kwesisindo) kanye nokudluliselwa komoya (ukugeleza kokushisa okuhambisana nokudluliselwa kwesisindo, njenge-mantle egeleza kancane). Umthetho kaFourier uchaza ukugeleza kokushisa okuqhubayo njengokuvumelana nokuphakama kokushisa kanye nokuhanjiswa kwesisindo.
Ukulinganiswa kwe-geothermal gradients, i-heat fluxes, kanye nezakhiwo zokushisa zamatshe kusiza ukuqonda izinhlelo ze-geothermal, i-metamorphism, kanye ne-tectonic dynamics. Ezindaweni ze-subduction, isibonelo, amaphethini okushisa athonywa amapuleti e-subducting, ukujikeleza koketshezi, kanye nokungqubuzana endaweni yokuxhumana. Ezindaweni eziphakathi nolwandle, ukuphakama kwezinto ezishisayo kwandisa i-heat flux futhi kwakha izinhlelo ze-hydrothermal.
7. Ubudlelwano phakathi kwezakhiwo zomzimba kanye nokuchazwa: inkinga yokuguqulwa kanye nokungahlukile
Ingqikithi ye-geophysics akuyona nje ukulinganisa, kodwa ukuhumusha. Ukulinganisa okusebusweni noma okuvela emithonjeni yasemoyeni noma yesathelayithi kumele kuhunyushwe kube amamodeli angaphansi komhlaba. Le nqubo ibizwa ngokuthi i-inversion. Ngokwemvelo nangokwezibalo, ukuguquguquka kuvame ukungavamile: amamodeli amaningi angachaza idatha efanayo. Ngakho-ke, i-geophysics yanamuhla incike ezimisweni zokuhlelwa kabusha, izibalo, kanye nokuhlanganiswa kwedatha eminingi.
Isibonelo, i-gravity anomaly ingabonisa ukuba khona komzimba onabantu abaningi, kodwa ayibonisi ngqo ukuthi kungukungena kwe-basalt noma i-metal ore—kokubili kungenzeka. Ngokufaka idatha ye-magnetic, i-seismic, noma i-EM, ukuhumusha kuba okuqinile futhi okungokoqobo.
8. Isikali kanye nenhloso: kusukela ekuhloleni kuya ekuqondeni umhlaba womhlaba wonke
Izimiso zefiziksi yoMhlaba ku-geophysics zisebenza kuzo zonke izikali. Esikalini somhlaba wonke, i-satellite seismology kanye namandla adonsela phansi kusiza ekubaleni ukungafani kokujikeleza komhlaba, i-geoid, kanye nokujikeleza kwangaphakathi. Ezikalini zesifunda nezendawo, izindlela ze-geophysical zisetshenziselwa ukuhlola izinsiza (uwoyela, igesi, amaminerali, i-geothermal), ukunciphisa izinhlekelele (ukuqapha izintaba-mlilo, ukuzungeza komhlaba okuncane), ubunjiniyela be-geotechnical (ukuzinza kwesisekelo), kanye nezifundo zemvelo (ukungcola kwenhlabathi namanzi).
Okuzihlanganisa zonke isimiso sokuthi ukwehluka kwezakhiwo zomzimba—ubuningi, ukunwebeka, ukuhanjiswa kwamandla kagesi, ukwenziwa kwamandla kagesi, kanye nokushisa—kuhlobene ngqo nezinqubo ze-geological. Izindlela ze-geophysical zinikeza ithuba lokuthola lokhu kwehluka ngokwenani.
I-Penutup
Izimiso eziyisisekelo zefiziksi yoMhlaba ku-geophysics zingafingqwa njengomzamo wokuqonda uMhlaba ngezimpendulo zomzimba ezilinganisekayo: amandla adonsela phansi kanye nemagnetism njengezinkambu ezingaba khona, ukuzamazama komhlaba njengokusabalala kwamagagasi anwebekayo, izindlela zikagesi kanye ne-electromagnetic njengezimpendulo zokuqhuba kanye nokungenisa, kanye ne-geothermal njengokugeleza kokushisa kwangaphakathi. Indlela ngayinye inamandla kanye nemikhawulo, ikakhulukazi ehlobene nokungahlukile kokuhumusha, ngakho ukuhlanganiswa kwedatha kanye nokuqonda ifiziksi yezinto ezibonakalayo kubalulekile.
Njengoba inesisekelo esiqinile ku-physics, i-geophysics ingahlanganisa ukubonwa okungaphezulu neqiniso eliyinkimbinkimbi elingaphansi kwayo—ukusiza abantu baqonde isakhiwo soMhlaba, basebenzise izinsiza zawo ngendlela efanele, futhi banciphise izingozi zezinhlekelele ngokusebenzisa amamodeli nokuqapha okungcono.
