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Bolshoi Semiachik

Stratovolcano(es) in Russia

Last Eruption: -4450

Key Facts

Elevation

1,720 m (5,643 ft)

Type

Stratovolcano(es)

Location

54.320°, 160.020°

Region

Eastern Kamchatka Volcanic Arc

Rock Type

Basalt / Picro-Basalt

Tectonic Setting

Subduction zone

Location

Loading map...

Overview

The Bolshoi Semiachik volcanic complex was constructed within a 10-km-wide caldera whose rim is exposed only on the west. The caldera occupies a large 20 x 30 km late-Pleistocene volcano-tectonic depression near the Pacific Coast of eastern Kamchatka. Post-caldera volcanism includes resurgent doming and the construction of numerous stratovolcanoes and lava domes, several of which have been active during the Holocene.

Zubchatka (Bolshoi Semiachik), Zapadny Barany, Vostochny Barany, Zentralny Semiachik, Popkov, Plosky, and Burlyashchy volcanoes are the largest of the complex. The youngest volcanism and intense hydrothermal activity is located outside the caldera to the SE.

Volcanic Hazards & Risk Assessment

Primary Hazards

    Risk Level

    Population at RiskModerate
    Infrastructure RiskModerate
    Aviation RiskSignificant

    Geological Composition & Structure

    Rock Types

    Primary
    Basalt / Picro-Basalt
    Silica Content
    Low (45-52% SiO₂)

    Tectonic Setting

    Subduction zone
    Formed by oceanic plate subduction, typically producing explosive eruptions due to water-rich magmas.

    Age & Formation

    Epoch
    Holocene
    Evidence
    Eruption Dated

    Eruption Statistics & Analysis

    MetricValueGlobal RankingSignificance
    Total Recorded EruptionsUnknownLowModerately active volcano
    Maximum VEIVEI UnknownMinorLocal impact potential
    Recent Activity6476 years agoHistoricalHistorically active

    Monitoring & Alert Status

    Monitoring Networks

    Global Volcanism Program
    International eruption database

    Current Status

    Normal
    No recent activity. Routine monitoring continues.

    Nearby Volcanoes in Northwestern Pacific Volcanic Regions

    Regional Volcanic Activity
    The Northwestern Pacific Volcanic Regions contains multiple active volcanic systems. Cross-regional magma interactions and tectonic stresses can influence eruption patterns across the entire arc. Monitor regional seismic activity and volcanic alerts.

    Quick Info

    • •Smithsonian ID: 300150
    • •Evidence: Eruption Dated
    • •Epoch: Holocene

    About the Photo

    Bolshoi Semiachik is a group of late Pleistocene-Holocene cones and domes located within a large caldera. The massif is seen here from the western rim (Bort ridge). Bolshoi Semiachik volcano is the large late-Pleistocene edifice on the near the center of the horizon. Several Holocene extrusive domes and vigorously active thermal fields are located W and SW of the volcano.

    Copyrighted photo by Nikolai Smelov (Holocene Kamchataka volcanoes; http://www.kscnet.ru/ivs/volcanoes/holocene/main/main.htm).

    Authority Sources

    Smithsonian GVP
    Official volcano database
    USGS Volcano Hazards
    U.S. Geological Survey
    Global Volcanism Program
    Smithsonian Institution

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    Basic Information

    This page shows basic data from the Smithsonian Global Volcanism Program. For more detailed information, visit the official Smithsonian page.