Estados Unidos · Volcán en escudo
Monte Okmok
Okmok
- Tipo
- Volcán en escudo
- Altitud
- 1073 m
- Última erupción
- 2008
- Tipo
- Volcán en escudo
- País
- Estados Unidos
- Región
- América del Norte / Aleutian Ridge Volcanic Arc
- Altitud
- 1073 m
- Coordenadas
- 53.430, -168.130
- Última erupción
- 2008
- Contexto tectónico
- Zona de subducción / Corteza intermedia (15-25 km)
- Forma volcánica
- Escudo
- Roca principal
- Basalto / Picrobasalto
Resumen geológico
The basaltic Okmok shield volcano forms the NE end of Umnak Island in the Aleutian Islands. The summit of the low, 35-km-wide volcano is cut by two overlapping 10-km-wide calderas formed during eruptions about 12,000 and 2,050 years ago when dacitic pyroclastic flows reached the coast. More than 60 tephra layers from Okmok have been found overlying the 12,000-year-old caldera-forming tephra layer. Numerous cones and lava domes are present on the flanks down to the coast, including the SE-flank Mount Tulik, which is almost 200 m higher than the caldera rim. Some of the post-caldera cones show evidence of wave-cut lake terraces; more recent cones were formed after the caldera lake, once 150 m deep, disappeared. Eruptions have been reported since 1805 from cinder cones within the caldera, where there are also hot springs and fumaroles.
Resumen de Wikipedia
Resumen en inglésMount Okmok is a volcano on eastern Umnak Island, in the central-eastern Aleutian Islands of Alaska. Part of the Aleutian Volcanic Arc, it was formed by the subduction of the oceanic Pacific Plate under the North American Plate. Okmok is a large shield volcano capped by a 10-kilometer (6.2 mi) wide caldera. The caldera contains numerous cinder cones, their lava flows, and a few lakes. Okmok erupts mainly basaltic lava, mostly from the cones within the caldera.
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Historial de erupciones
19 registradasGlosarioLínea de tiempo detallada
- 2008VEI 4Observado2008-07-12 – 2008-08-19NE caldera floor
- 1997VEI 3Observado1997-02-11 – 1997-05-19SW part of caldera (Cone A)
- 1986VEI 2Observado1986-11-18 – 1988-02-26SW part of caldera (Cone A)
- 1983VEI 2Observado1983-07-08 – 1983-07-08SW part of caldera (Cone A)
- 1981VEI 3Observado1981-03-24 – 1981-03-24SW part of caldera (Cone A)
- 1960VEI 3Observado1960-10-15 – 1961-04-15SW part of caldera (Cone A)
- 1958VEI 3Observado1958-08-14 – 1958-08-25SW part of caldera (Cone A)
- 1945VEI 2Observado1945-06-04 – 1945-12-16SW part of caldera (Cone A)
- 1943VEI 1Observado1943-06-16 – fin desconocidoSW part of caldera (Cone A)
- 1938VEI ?Observado1938-07-02 – fin desconocidoSW part of caldera (Cone A)
- 1936VEI ?Método no indicado1936-07-02 – fin desconocidoSW part of caldera (Cone A)
- 1931VEI 2Observado1931-03-21 – 1931-05-13Cone A?
- 1899VEI 3Observado1899-07-02 – fin desconocidoSW part of caldera (Cone A)
- 1878VEI 2Observado1878-07-02 – fin desconocidoCone A?
- 1824VEI ?Observado1824-07-02 – 1830-07-02Cone B?
- 1817VEI 3Observado1817-03-01 – 1820-07-02Cone E? or B?
- 1805VEI ?Observado1805-07-02 – fin desconocido
- 100 a. C. (±50 años)VEI 6Estimación geológica100 a. C. – fin desconocidoOkmok II caldera
- 6310 a. C. (±500 años)VEI 4Estimación geológica6310 a. C. – fin desconocido
Volcanes cercanos
Enlaces externos
⚠ Solo como referencia. No apto para respuesta ante emergencias.