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North Gorda Ridge Segment

Fissure vent(s) in United States

Last Eruption: 1996

Key Facts

Elevation

-3,000 m (-9,843 ft)

Type

Fissure vent(s)

Location

42.670°, -126.780°

Region

Northeast Pacific Rifts Volcanic Province

Rock Type

Basalt / Picro-Basalt

Tectonic Setting

Rift zone

Location

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Overview

The northernmost of five segments of the Gorda Ridge lies immediately south of the Blanco Transform Fault that offsets the Gorda and Juan de Fuca oceanic spreading ridges. The 65-km-long segment is located about 200 km W of the southern Oregon coast and has deep 5- 10-km-wide valleys at either ends with a shallower narrow axial valley at the center. This morphology, which in plan view resembles an hourglass, is typical of magmatically active spreading segments.

A submarine lava flow was erupted in late February and early March 1996, near the center of the segment. The eruption was initially detected through acoustic T-waves from a seismic swarm and the emission of large thermal plumes. In April submarine cameras revealed new lava flows about 100-200 m wide along a fissure that was at least 3.

5 km long. A seismic swarm of uncertain origin also occurred at this location in January 1998.

Volcanic Hazards & Risk Assessment

Primary Hazards

    Risk Level

    Population at RiskModerate
    Infrastructure RiskHigh
    Aviation RiskSignificant

    Geological Composition & Structure

    Rock Types

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

    Tectonic Setting

    Rift zone
    Continental rift or intraplate setting with varied eruptive styles.

    Age & Formation

    Epoch
    Holocene
    Evidence
    Eruption Observed

    Eruption Statistics & Analysis

    MetricValueGlobal RankingSignificance
    Total Recorded EruptionsUnknownLowModerately active volcano
    Maximum VEIVEI UnknownMinorLocal impact potential
    Recent Activity30 years agoRecentRecently active

    Monitoring & Alert Status

    Monitoring Networks

    Global Volcanism Program
    International eruption database

    Current Status

    Watch
    Dormant but monitored. Capable of renewed activity.

    Nearby Volcanoes in Eastern Pacific Volcanic Regions

    Regional Volcanic Activity
    The Eastern 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: 331031
    • Evidence: Eruption Observed
    • Epoch: Holocene

    About the Photo

    This lava flow was erupted in 1996 along the North Gorda Ridge, the northernmost of five segments of the Gorda Ridge located immediately south of the Blanco Transform Fault, which offsets the Gorda and Juan de Fuca spreading ridges. Submarine cameras revealed new lava flows about 100-200 m wide along a fissure that was at least 3.5 km long. The 65-km-long North Gorda Ridge segment is located about 200 km W of the southern Oregon coast and has an hourglass shape in plan view, with a shallower narrow axial valley at the center.

    Image courtesy of National Oceanic and Atmospheric Administration, 1996 (http://www.pmel.noaa.gov/vents/home.html).

    Basic Information

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