Volcano Name

Mount Spurr

Type

Stratovolcano (also called a composite volcano)

Location

Alaska, USA Part of Aleutian Volcanic Arc located approximately 80 miles (130 km) west of Anchorage

Elevation

Approximately 11,070 feet (3,374 meters) above sea level

Coordinates

61.299°N, 152.251°W

Geological Zone

Located along Pacific Ring of Fire a seismically active area of subduction zones around Pacific Ocean

Volcanic Arc

Aleutian Arc Formed due to subduction of Pacific Plate beneath North American Plate

Nearby Features

Lies near Cook Inlet; neighboring volcanoes include Redoubt & Augustine

Crater Peaks

Summit Peak Main cone
Crater Peak A satellite vent (4.3 miles south) source of recent eruptions

1953

Explosive eruption from Crater Peak

Produced ash clouds that disrupted air traffic.

1992

VEI-4 eruption from Crater Peak

Series of eruptions July–September; ash fall reached Anchorage; significant air traffic disruptions in Southcentral Alaska.

Historical

Lava flows, ash plumes

Mount Spurr has been active over Holocene epoch producing andesitic to dacitic lava flows & tephra.

Alert Level

YELLOW (Advisory) Elevated signs of unrest without confirmed eruption

Gas Emissions

High levels of CO₂ measured at summit & crater peak (detected during March 2025 AVO flight)

Steam/Gas Vents

Newly opened gas vents emitting visible steam & volcanic gases

Earthquake Swarm

Over 3,400 earthquakes recorded under volcano since April 2024 with more than 100 per week recently

Volcanic Gas Composition

Primarily CO₂, with SO₂ & H₂S likely components (typical for pre-eruptive degassing)

Seismicity Trends

Earthquakes are mostly low-magnitude (< M3.0), shallow & clustered below Crater Peak indicating magma movement or pressurization

Surface Changes

Signs of surface heating & increased fumarolic activity observed during aerial surveillance

AVO Monitoring Tools

Seismometers
Infrasound stations
Gas sensors
Satellite thermal imaging
Aerial overflights

Potential Eruption Window

Observers estimate eruption could occur in next weeks to months if unrest escalates

Seismic Monitoring

Earthquake frequency, depth & location indicate magma movement

Gas Emissions

Elevated CO₂ & SO₂ suggest degassing of rising magma

Ground Deformation

Monitored using GPS & InSAR satellites to detect inflation from magma accumulation

Thermal Imaging

Used to detect increased surface temperatures & potential lava activity

Historical Comparison

Patterns compared with 1992 & 1953 eruptions short-duration ash-rich events

Proximity to Anchorage

At just 80 miles ash fallout & air travel disruption pose a significant hazard to populated areas

Air Traffic Disruption

Ash plumes from previous eruptions (e.g. 1992) severely disrupted flights in Southcentral Alaska

Ashfall Zones

Ash clouds can travel far impacting regions hundreds of kilometers away especially during wind events

Human Risk

Remote location means low direct hazard to life but economic & transport disruptions are expected

Pacific Ring of Fire

Mount Spurr is part of one of world’s most volcanically & seismically active regions

Tectonic Setting

Subduction of Pacific Plate beneath North American Plate key driver of Aleutian Arc volcanism

Comparative Volcanoes

Nearby volcanoes like Redoubt, Augustine & Katmai have similar eruptive styles & hazards

PRACTICE QUESTION

Q. Volcanoes along subduction zones like Aleutian Arc pose both regional & global risks." Examine tectonic setting of Mount Spurr & its implications for disaster management.