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Maar Ukinrek

Ukinrek Maars

Maar · United States · 91 m

Ukinrek Maars are two phreatomagmatic explosion craters that were created in an area without previous volcanic activity during a 10-day-long eruption that began on 30 March 1977. A greenish lake fills East Maar, the largest of the two in this 1994 view from the south. The smaller West Maar is surrounded by dark tephra near the left margin. Gas Rocks, an older volcanic center, forms the peninsula extending into Becharof Lake in the background.
Ukinrek Maars are two phreatomagmatic explosion craters that were created in an area without previous volcanic activity during a 10-day-long eruption that began on 30 March 1977. A greenish lake fills East Maar, the largest of the two in this 1994 view from the south. The smaller West Maar is surrounded by dark tephra near the left margin. Gas Rocks, an older volcanic center, forms the peninsula extending into Becharof Lake in the background. · Foto: Photo by Chris Nye, 1994 (Alaska Division of Geological and Geophysical Surveys, Alaska Volcano Observatory). · Wikimedia Commons
Tipe
Maar
Negara
United States
Wilayah
North America Volcanic Regions / Alaska Peninsula Volcanic Arc
Ketinggian
91 m
Koordinat
57.834, -156.520
Letusan terakhir
1977
Kondisi tektonik
Subduction zone / Continental crust (> 25 km)
Bentuk lahan
Minor (Basaltic)
Batuan utama
Basalt / Picro-Basalt
Ringkasan geologi

Ukinrek Maars are two explosion craters that were created in an area without previous volcanic activity during a 10-day phreatomagmatic eruption March-April 1977. The basaltic maars were erupted through glacial deposits in the Bering Sea lowlands 1.5 km S of Becharof Lake and 12 km W of Peulik volcano; their location is related to the regional Bruin Bay fault. The elliptical West Maar, which was the first to form, is 105 x 170 m and 35 m deep. The other maar, 600 m to the east, is 300 m wide and 70 m deep. Both maars are now filled by crater lakes; the eastern lake encircles a 49-m-high lava dome that was emplaced at the end of the eruption. Base surges were directed primarily to the NW. Juvenile material from the Ukinrek eruptions was of mantle-derived olivine basaltic composition. The dacitic Gas Rocks lava domes, of Quaternary age, are located on the shores of Becharof Lake, 3 km N of Ukinrek maars and were the site of a phreatic eruption about 2,300 years ago.

Ringkasan Wikipedia

Maar Ukinrek adalah dua kawah gunung berapi di sisi utara Pegunungan Aleut di Alaska yang terbentuk oleh letusan freatomagmatik pada tahun 1977. Maar tersebut berada 1,5 km di selatan Danau Becharof dan 12 km barat laut dari Gunung Berapi Peulik, berada di dataran rendah yang berbatasan dengan Laut Bering. Bagian barat keduanya berbentuk elips dengan diameter mencapai 170 m dan berkedalaman 35 m. Yang lainnya terletak 600 m ke timur dan berbentuk lingkaran dengan diameter hingga 300 m dan berkedalaman 70 m. Maar sebelah timur mempunyai kubah lava setinggi 49 m di dalam danau kawahnya.

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Riwayat letusan

Ringkasan (VEI dari waktu ke waktu)
Klik pada bar untuk melihat letusan individu
350 BCE~156 BCE · 1 letusan · VEI maks. ?1783~1977 · 1 letusan · VEI maks. 3350 BCE23281412011783

Garis waktu rinci

  1. 1977VEI 3Teramati
    1977-03-30 – 1977-04-09
    West and East Ukinrek Maars
  2. 350 SMVEI ?Perkiraan geologi
    BCE 350 – Berlangsung
    Gas Rocks

Tautan eksternal

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