El INtaba i-Saint Helena iyintabamlilo eqhumayo eNyakatho Melika, ekhuphuka ngokubabazekayo eningizimu-ntshonalanga yesifunda saseWashington e-United States. Igama layo lesiNgisi yi-St. Helens, kanti amaqembu aboMdabu baseMelika ayibiza ngokuthi iLawetlat'la, iLawalaclough, neTahonelatclah. Igama layo lamanje livela ku-Elaine Fitzherbert, XNUMXst Baron wase-Saint Helena kanye nomngane womhloli wamazwe uGeorge Vancouver, owahlola indawo lapho ingaziwa kancane.
Kulesi sihloko sizokutshela zonke izici, imvelaphi, i-geology kanye nokuqhuma kweNtaba i-Saint Helena.
Indawo
I-Mount Saint Helens iyindawo eyaziwayo yokwakhiwa kwentaba-mlilo etholakala eScamania County, Washington State, ePacific Northwest Territory yase-United States of America. Cishe ngamamitha angu-2.550 ngaphezu kwezinga lolwandle, igama elithi "current" lisetshenziswa ngenxa yokuthi ukuqhuma kwayo okubhalwe kabanzi kuye kwehlisa ukuphakama kwalesi sakhiwo sentaba-mlilo.
Itholakala ncamashi kumakhilomitha angu-154 ukusuka eSeattle futhi cishe amakhilomitha angu-85 enyakatho-ntshonalanga yePortland, Oregon. Lesi sakhiwo esikhulu sentaba-mlilo siyingxenye yeCascade Range, futhi le ndawo ekuqaleni yaziwa ngegama elithi Louwala-Clough, okusho ukuthi "intaba-mlilo eshunqayo noma intaba," ngolimi lwalabo okuthiwa abantu basendaweni abadumile, isizwe sendawo esibizwa ngokuthi iKlickitat.
I-Saint Helena ithola igama layo kunxusa u-Erin Fitzherbert, ngoba wayenguBaron wokuqala waseSaint Helena, umngane omkhulu wesakhamuzi sikaGeorge Vancouver, umhloli wamazwe omkhulu nonelukuluku lokwazi owayephethe ukuhlola indawo yekhulu leshumi nesishiyagalombili eSanta Helena. Intaba-mlilo yaziwa ngokuqhuma kwayo okukhulu okuqukethe amanani amakhulu omlotha nalokho okubizwa ngokuthi ukugeleza kwe-pyroclastic.
Ukwakhiwa kweMount Saint Helens
Uma iqhathaniswa nezinye izintaba-mlilo eCascade Range, iMount Saint Helens iyintaba-mlilo esencane kakhulu. Ngokusho kwe-United States Geological Survey (USGS), ukwakheka kwayo Kwenzeke ngezigaba ezi-4 zokuqhuma okwaqala eminyakeni engaba ngu-275.000 edlule, nakuba iSmithsonian Institution Global Volcanic Activity Programme ibonisa ukuthi yaqala ngezigaba ezingu-9 ezakhiwe eminyakeni engu-40.000-50.000 edlule ngesikhathi sokuqhuma. Kunoma yikuphi, phakathi neHolocene kwakuyiyona eqhuma kakhulu kuzo zonke izintaba-mlilo eCordillera.
Uhlelo lwe-USGS Volcanic Hazards lubonisa ukuthi lutholakala eduze nendawo encishisiwe yepuleti le-Juan de Fuca ogwini olusentshonalanga ye-United States futhi liwumphumela wokunyakaza okukhulu koqweqwe lomhlaba.
Esikhathini esiyiminyaka engu-12.800 XNUMX edlule, isigaxa sasendulo saseMount St. Helens. okwakhiwa ukuqhuma kokuqhuma kwentaba-mlilo, ama-lava domes, nokunye ukugeleza kwe-pyroclastic eyayifinyelela emazweni aqhelelene nesizinda sentaba-mlilo. Eminyakeni engu-3000 edlule, i-cone ithole isakhiwo sesimanje kakhulu. Ngakolunye uhlangothi, i-Global Volcanism Programme iphawula ukuthi i-cone yakhiwa ngokukhishwa kwe-lava ne-pyroclastic impahla esikhathini esithile ngaphambi kweminyaka engu-2200 edlule, kuyilapho ikhoni yesimanje iwukuqhubeka kwezingcezu ze-andesite, i-dacite, ne-basalt ezibangelwa ukugeleza.
Ukuqhuma kweMount Saint Helens
Ukuqhuma kwango-1980 kwakuyikona okwacwaningwa kakhulu ekhulwini lama-2340, kodwa izintaba-mlilo zinomlando omude wokuqhuma. Isenzakalo esidala esiqinisekisiwe senzeka ngo-1860 BC. C. Okunye ukuqhuma kwenzeka ngo-1180a. C, 1110. C, 100a. C, 420 BC C, AD 1831 C, ngo-August 26, March 1847, 27, March 1980, 5, November 1990, 1, no October 2004, XNUMX.
Ingqikithi yokuqhuma kwe-40 sekuqinisekisiwe ngokuhamba kwesikhathi, nokungaqiniseki okuthile. Kwaba nokuzamazama komhlaba ngaphansi kwentaba-mlilo ngo-March 20, 1980, futhi okunye ukuzamazama okungenamandla kakhulu kwenzeka phakathi komhla zingama-20 no-27 wenyanga efanayo. Emini nje ngomhlaka-27, insika yomlotha nesimusi yehla entabeni, yafinyelela ubude obungamamitha angu-1.829. Kodwa okubi kakhulu akuzange kwenzeke.
Ekuseni ngoMeyi 18, ukuzamazama komhlaba okunesilinganiso esingu-5.1 kwenzeka futhi ingxenye esenyakatho yentaba-mlilo yaqala ukubhidlika. okwenzeka kwaba ukudilika komhlaba kanye nokuqhuma kwe-Pliny amahora angu-9. Ikholomu yokuqhuma ibingamakhilomitha angu-24 ukuphakama futhi umlotha wathinta izingxenye zezifunda zase-US ezingu-11. Imali esele ifile abangu-57 (kuhlanganise nomthwebuli wezithombe kanye ne-geographer) kanye nezigidi zamaRandi emonakalweni wezomnotho.
ukuqhuma kokugcina
Kungashiwo ukuthi yonke into yaqala ncamashi ngoMashi 16, ikakhulukazi ngo-1980, yaba nesiqalo esikhethekile, mhlawumbe uchungechunge lokuzamazama komhlaba, okubonakala sengathi umsuka walo usekuhambeni okukhulu kwe-magma equkethwe entabeni yaseSanta Elena. Ukuzamazama komhlaba okujulile okuhambisana nesenzakalo sobukhulu obungu-4,2 esikalini sikaRichter kungase kubhaliswe ngale ndlela ngoMashi 20, kugcinwe indawo yesikhathi efanele nemisiwe, njengaleyo yasePacific Ocean, ephawulwe ngo-15:47.
Konke lokhu kungaphansi kwendawo engenhla esenyakatho yeNtaba i-St. Helens okukhulunywe ngayo ngenhla njengengqophamlando, okubonisa okubalulekile. umsebenzi wale ntaba-mlilo enkulu ngemva kweminyaka engaphezu kuka-123 ingasebenzi.
Kuthiwa ngemva kwalokhu kwanezelwa uchungechunge lokuzamazama komhlaba okuncane futhi ngandlela-thile wonke ama-seismometer afakwe kahle agcwala ngesikhathi kuthunyelwa yonke indawo, kwaze kwaba yilapho kufika isilinganiso esiphezulu phakathi kuka-March 25 nezinsuku ezimbili kamuva, phakathi nalezi zinsuku ezimbili ezimatasa kakhulu.
Inani elikhulu lokuzamazama komhlaba okungu-174 kwabhalwa ekuzamazameni komhlaba okudumile okungu-2,6 esikalini sikaRichter noma ngaphezulu. Kwaba ngemva kwalokhu ukuzamazama komhlaba kukhuphuke ngezinga lika-3.2 degrees futhi zazikhula izikhathi eziningi phakathi kuka-April no-May, ekuqaleni kuka-April, ngesizathu esithile, kwakunesilinganiso sokuzamazama komhlaba oku-5 okungama-degree angu-4 noma ngaphezulu nsuku zonke.
Kodwa ngesonto elandulela lokho, ngo-May 18, isilinganiso sase sizungeza inkathi yokuzamazama okungu-55 ngosuku, ekuqaleni kungekho ncanyana noma ubufakazi obuqondile bokuqhuma kwesikhathi esizayo, kodwa uhlobo oluthile lokuzamazama okuncane okubangela okukhulu. Njengoba kuboniswe ngenhla, ukuqoqwa kweqhwa neqhwa okubonwa emoyeni oqoshwe ama-avanches. Ngo-12:36 ebusuku ngoMashi 27, kwaba nokuqhuma okuwohlozayo ngandlela thize, futhi abantu abaningi bathi kwenzeka kabili ngesikhathi esisodwa.
Ngethemba ukuthi ngalolu lwazi ungafunda kabanzi ngeNtaba i-Saint Helena nezici zayo.