A cikin wani yanki mai nisa, haɗaɗɗun hanyoyin geophysical suna gano canjin magma a ƙasan tekun a matsayin sanadin.
Ko a bakin tekun Antarctica, ana iya samun duwatsu masu aman wuta. An yi rikodin jerin girgizar ƙasa sama da 85,000 a cikin 2020 a dutsen mai aman wuta na Orca, wanda ya daɗe ba ya aiki, girgizar ƙasar da ta kai adadin da ba a taɓa gani ba a wannan yanki. Gaskiyar cewa ana iya yin nazari da kuma bayyana irin waɗannan abubuwan dalla-dalla ko da a cikin irin wannan yanki mai nisa, sabili da haka wuraren da ba a iya amfani da su ba, yanzu ya nuna ta hanyar nazarin ƙungiyar ƙasa da ƙasa da aka buga a cikin mujallar. Sadarwa Duniya da Muhalli.
Masu bincike daga Jamus, Italiya, Poland, da Amurka sun shiga cikin binciken, wanda Simone Cesca na Cibiyar Nazarin Geosciences ta Jamus (GFZ) Potsdam ta jagoranci. Sun sami damar haɗa dabarun nazarin ƙasa, geodetic, da kuma dabarun gano nesa don sanin yadda saurin saurin magma daga rigar duniya kusa da kan iyakar ɓawon burodi zuwa kusan saman saman ya haifar da girgizar ƙasa.
Volcano na Orca tsakanin tip na Kudancin Amirka da Antarctica
Girgizar kasa ta fi faruwa a yankuna masu aman wuta. Don haka ana zargin motsin ruwaye a cikin ɓawon burodi a matsayin sanadin. Orca Seamount wani babban dutsen mai fitad da garkuwar teku ne mai tsayin kusan mita 900 sama da benen teku da diamita na tushe na kusan kilomita 11. Tana cikin mashigin Bransfield, tashar teku tsakanin yankin Antarctic Peninsula da tsibiran Shetland ta Kudu, kudu maso yamma da iyakar kudancin Argentina.
“A da, girgizar kasa a wannan yanki ya kasance tsaka-tsaki. Koyaya, a cikin Agusta 2020, wani mummunan girgizar ƙasa ya fara a can, tare da girgizar ƙasa sama da 85,000 a cikin rabin shekara. Yana wakiltar tashin hankali mafi girma da aka taɓa samu a wurin,” in ji Simone Cesca, masanin kimiya a Sashe na 2.1 na GFZ Girgizar ƙasa da Physics na Volcano kuma jagorar marubucin binciken da aka buga yanzu. A daidai lokacin da tururuwa, an yi rikodin ƙaura na gefe sama da santimita goma da ƙaramin ɗaga sama da kusan centimita ɗaya a makwabciyar tsibirin King George.
Kalubalen bincike a wuri mai nisa
Cesca yayi nazarin waɗannan abubuwan da suka faru tare da abokan aiki daga National Institute of Oceanography da Applied Geophysics - OGS da Jami'ar Bologna (Italiya), Cibiyar Kimiyyar Kimiyya ta Poland, Jami'ar Leibniz Hannover, Cibiyar Aerospace ta Jamus (DLR) da Jami'ar Potsdam. Kalubalen shine cewa akwai ƙananan kayan aikin girgizar ƙasa a cikin yanki mai nisa, wato seismic biyu kawai da tashoshi na GNSS guda biyu (tashoshin ƙasa na ƙasa). Gduniya Navigation Satellite System wanda ke auna ƙaura). Domin sake gina tarihin tarihi da ci gaban tashin hankali da kuma tantance musabbabin sa, ƙungiyar ta kuma yi nazarin bayanai daga manyan tashoshin girgizar ƙasa da bayanai daga tauraron dan adam InSAR, waɗanda ke amfani da radar interferometry don auna ƙaura. Wani muhimmin mataki shine ƙirar abubuwan da suka faru tare da hanyoyi masu yawa na geophysical don fassara bayanai daidai.
Sake gina abubuwan girgizar kasa
Masu binciken sun yi watsi da fara tashin hankalin zuwa 10 ga Agusta 2020 kuma sun tsawaita kasida ta asali ta girgizar kasa ta duniya, wacce ke dauke da girgizar kasa 128 kawai, zuwa sama da abubuwan 85,000. Girgizar kasa ta yi kololuwa da manyan girgizar kasa guda biyu a ranar 2 ga Oktoba (Mw 5.9) da 6 ga Nuwamba (Mw 6.0) 2020 kafin ta ragu. A watan Fabrairun 2021, ayyukan girgizar ƙasa ya ragu sosai.
Masanan kimiyya sun gano kutsen magma, ƙaura mai girma girma na magma, a matsayin babban dalilin girgizar girgizar ƙasa, saboda tsarin girgizar ƙasa kaɗai ba zai iya bayyana nakasar da aka gani mai ƙarfi a kan tsibirin King George. Ana iya tabbatar da kasancewar kutsawar magma volumetric da kansa bisa ga bayanan geodetic.
Tun daga asalinsa, seismicity ya fara ƙaura zuwa sama sannan kuma a gefe: zurfi, girgizar ƙasa mai tari ana fassara shi azaman martani ga yaduwar magma a tsaye daga tafki a cikin rigar sama ko a kan iyakar ɓawon burodi, yayin da ƙasa mai zurfi, girgizar ƙasa ta ƙara NE-SW. ya taso a saman digon magma dake girma a kaikaice, wanda ya kai tsawon kimanin kilomita 20.
Girgizar kasa ta ragu kwatsam zuwa tsakiyar watan Nuwamba, bayan kimanin watanni uku na ci gaba da gudanar da ayyuka, daidai da aukuwar girgizar kasa mafi girma a cikin jerin, tare da girman Mw 6.0. Za'a iya bayyana ƙarshen raƙuman ruwa ta hanyar asarar matsa lamba a cikin magma dike, tare da zamewar babban kuskure, kuma zai iya nuna lokacin fashewar teku wanda, duk da haka, wasu bayanai ba za su iya tabbatar da su ba.
Ta hanyar yin ƙirar bayanan GNSS da InSAR, masana kimiyya sun kiyasta cewa ƙarar kutsawar Bransfield magmatic yana cikin kewayon 0.26-0.56 km³. Wannan ya sa wannan lamarin ya zama tashin hankali mafi girma da aka taɓa sa ido a kai a cikin Antarctica.
Kammalawa
Simone Cesca ta kammala da cewa: “Bincikenmu yana wakiltar wani sabon bincike mai nasara na rikicin girgizar ƙasa mai aman wuta a wani wuri mai nisa a Duniya, inda ake amfani da haɗin gwiwar ilimin kimiyyar ƙasa, geodesy, da dabarun gano nesa don fahimtar hanyoyin girgizar ƙasa da jigilar magma cikin ƙarancin kayan aiki. yankunan. Wannan yana ɗaya daga cikin 'yan lokuta inda za mu iya amfani da kayan aikin geophysical don lura da kutsawa na magma daga saman rigar ko ɓawon burodi a cikin ƙananan ɓawon burodi - saurin canja wurin magma daga rigar zuwa kusan saman da ke ɗaukar kwanaki kaɗan kawai. .”
Magana: "Gwamnatin girgizar ƙasa mai girma ta kutsawa a Bransfield Strait, Antarctica" na Simone Cesca, Monica Sugan, Łukasz Rudzinski, Sanaz Vajedian, Peter Niemz, Simon Plank, Gesa Petersen, Zhiguo Deng, Eleonora Rivalta, Alessaton, Alessaton. Plasencia Linares, Sebastian Heimann da Torsten Dahm, 11 Afrilu 2022, Sadarwa Duniya da Muhalli.
DOI: 10.1038/s43247-022-00418-5
