El Dutsen Saint Helena Dutsen mai aman wuta ne a Arewacin Amurka, yana tashi da ban mamaki a kudu maso yammacin jihar Washington a Amurka. Sunan Ingilishi St. Helens, kuma Ƙungiyoyin 'Yan asalin ƙasar Amirka suna kiransa da Lawetlat'la, Lawalaclough, da Tahonelatclah. Sunansa na yanzu ya fito ne daga Elaine Fitzherbert, Baron XNUMXst na Saint Helena kuma abokin mai binciken George Vancouver, wanda ya bincika yankin lokacin da ba a san shi ba.
A cikin wannan labarin za mu gaya muku duk halaye, asali, ilimin ƙasa da fashewar Dutsen Saint Helena.
Yanayi
Dutsen Saint Helens sanannen sanannen nau'in volcano ne wanda yake a cikin gundumar Scamania, jihar Washington, a cikin yankin Pacific Northwest Territory na Amurka ta Amurka. A kimanin mita 2.550 sama da matakin teku, ana amfani da kalmar "na yanzu". saboda fashe-fashen fashe-fashe da aka yi da yawa sun rage tsayin wannan dutsen mai aman wuta.
Tana daidai da nisan kilomita 154 daga Seattle da kimanin kilomita 85 arewa maso yammacin Portland, Oregon. Wannan katafaren ginin dutsen mai aman wuta yana cikin yankin Cascade Range, kuma asalin wurin an san shi da sunan Louwala-Clough, wanda ke nufin "Tsawon tsaunuka mai hayaki ko dutse," a cikin yaren da ake kira fitattun 'yan kasar, kabilar da ake kira Klickitat.
Saint Helena bashi da suna ga jami'in diflomasiyyar Erin Fitzherbert, tun da shi ne baron farko na Saint Helena. babban abokin ɗan ƙasa na George Vancouver, babban mai bincike mai ban sha'awa wanda ke kula da duba yankin karni na sha takwas a Santa Helena. An san dutsen mai aman wuta saboda manyan fashe-fashe masu dauke da toka mai yawan gaske da kuma abin da ake kira kwararar ruwa.
Samuwar Dutsen Saint Helens
Idan aka kwatanta da sauran tsaunukan tsaunuka a cikin Range na Cascade, Dutsen Saint Helens ɗan ƙaramin wuta ne. A cewar Cibiyar Nazarin Kasa ta Amurka (USGS), samuwar ta Ya faru a cikin matakai 4 na fashewa wanda ya fara kimanin shekaru 275.000 da suka wuce. ko da yake Cibiyar Ayyukan Ƙasa ta Duniya ta Smithsonian ta nuna cewa ta fara ne a cikin matakai 9 da aka kafa shekaru 40.000-50.000 da suka wuce yayin fashewar. A kowane hali, a lokacin Holocene shi ne mafi yawan aiki a cikin dukan tsaunuka a cikin Cordillera.
Shirin Hatsarin Volcanic na USGS yana nuna cewa yana kusa da yankin da aka rushe na farantin Juan de Fuca a yammacin gabar tekun Amurka kuma sakamakon babban motsi ne na ɓawon ƙasa.
A cikin shekaru 12.800 da suka wuce, tsohon mazugi na Dutsen St. Helens An kafa ta ta hanyar fashewar fashewar dutsen mai aman wuta, domes na lava, da sauran kwararan ruwa na pyroclastic wanda ya kai filaye masu nisa daga gindin dutsen mai aman wuta. A cikin shekaru 3000 da suka gabata, mazugi ya sami mafi kyawun tsarin zamani. A nata bangaren, Shirin Volcanism na Duniya ya ambaci cewa an samar da mazugi ta hanyar sakin lava da kayan pyroclastic kafin shekaru 2200 da suka gabata, yayin da mazugi na zamani ci gaba ne na gutsuttsuran andesite, dacite, da basalt da ke fitowa daga kwarara.
Dutsen Saint Helens ya fashe
Fashewar 1980 ita ce mafi nazari a cikin karni na 2340, amma dutsen mai aman wuta yana da dogon tarihin fashewa. Babban abin da aka tabbatar ya faru a shekara ta 1860 BC. C. Wasu fashewa sun faru a cikin 1180a. C, 1110. C, 100a. C, 420 BC C, AD 1831 C, ranar Agusta 26, Maris 1847, 27, Maris 1980, 5, Nuwamba 1990, 1, da Oktoba 2004, XNUMX.
An dai tabbatar da bullar fashewar guda 40 a tsawon lokaci, tare da wasu rashin tabbas. Girgizar kasa ta afku a karkashin dutsen mai aman wuta a ranar 20 ga Maris, 1980, da wasu girgizar kasa da ba su da karfi sun faru tsakanin ranakun 20 zuwa 27 ga wannan wata. Da tsakar rana ranar 27 ga wata, wani ginshiƙin toka da tururi ya fito daga dutsen, wanda ya kai tsayin mita 1.829. Amma mafi muni bai faru ba.
A safiyar ranar 18 ga watan Mayu, girgizar kasa mai karfin awo 5.1 ta afku, kuma bangaren arewacin dutsen mai aman wuta ya fara rugujewa. abinda ya faru shine zaftarewar kasa da fashewar Pliny na awa 9. Rukunin fashewar ya kai kilomita 24 kuma tokar ta taba wasu sassa na jihohin Amurka 11. Matsakaicin ya mutu 57 (ciki har da mai daukar hoto da mai daukar hoto) da kuma lalacewar miliyoyin daloli.
fashewar karshe
Ana iya cewa duk abin da ya fara daidai a ranar 16 ga Maris, musamman ma a cikin 1980, yana da farkon farawa na musamman, mai yiwuwa jerin girgizar asa, wanda asalinsa ya kasance a cikin babban motsi na magma da ke cikin dutsen Santa Elena. Girgizar kasa mai zurfi da ta yi daidai da wani lamari mai ma'aunin Richter 4,2 a ma'aunin Richter ana iya yin rajista ta wannan hanya a ranar 20 ga Maris, tare da kiyaye yankin lokaci mai dacewa da daidaitacce, kamar na Tekun Pacific, mai alama a 15:47.
Duk wannan ya ta'allaka ne a ƙarƙashin saman dutsen arewacin da aka ambata a baya St. Helens a matsayin cibiyar tsakiya, yana nuna mahimmanci. ayyukan wannan babban dutsen mai aman wuta bayan fiye da shekaru 123 na rashin aiki.
An ce bayan wannan an kara wasu jerin kananan girgizar kasa kuma ko ta yaya dukkan na'urorin da aka sanya daidai da na'urar girgizar kasa sun cika yayin da ake tura yankin gaba daya, har sai da ya kai matsakaicin tsakanin 25 ga Maris zuwa kwana biyu, a cikin wadannan kwanaki biyu masu cike da cikawa.
An sami adadi mai yawa na girgizar ƙasa 174 a cikin shahararrun girgizar ƙasa na 2,6 akan ma'aunin Richter ko sama da haka. Bayan haka ne girgizar kasa ta karu a ma'aunin digiri 3.2 sannan kuma suna karuwa a tsakanin Afrilu da Mayu, a farkon watan Afrilu, saboda wasu dalilai, ana samun matsakaitan girgizar kasa 5 na kimanin digiri 4 ko fiye a kowace rana.
Sai dai a satin da ya gabata, a ranar 18 ga watan Mayu, matsakaita sun yi ta shawagi da girgizar kasa har sau 55 a rana, da farko ba tare da wata alama ko wata shaida ta kai tsaye ba, na fashewar fashewar nan gaba, sai dai wani nau'i na karamar girgizar da ke haddasa babbar. Kamar yadda aka nuna a sama, dusar ƙanƙara da tarin ƙanƙara da aka gani daga iskar da aka yi rikodin dusar ƙanƙara. Da misalin karfe 12:36 na dare a ranar 27 ga Maris, an samu fashewar wani abu mai kama da wuta, kuma mutane da yawa sun ce lamarin ya faru sau biyu a lokaci guda.
Ina fatan da wannan bayanin zaku iya ƙarin koyo game da Dutsen Saint Helena da halayensa.