Hijiori

Caldera in Japan

Key Facts

Elevation

552 m (1,811 ft)

Type

Caldera

Location

38.599°, 140.162°

Region

Northeast Japan Volcanic Arc

Rock Type

Dacite

Tectonic Setting

Subduction zone

Location

Loading map...

Overview

Hijiori caldera is a small, inconspicuous caldera located NE of the Pleistocene Gassan stratovolcano. The low 2. 5-km-wide caldera formed during a large eruption about 10,300 radiocarbon years ago.

This eruption was accompanied by dacitic pyroclastic flows and tephra fall that extended to the east and reached the Pacific coast and growth of a lava dome. Small local tephra deposits overlie lacustrine deposits. Hot springs occur at Hijiori, and caldera lake deposits have undergone extensive hydrothermal alteration.

Volcanic Hazards & Risk Assessment

Primary Hazards

Pyroclastic flows and surges
Large explosive eruptions (VEI 4+)
Ash fall and tephra deposits
Lahars and debris flows

Risk Level

Population at RiskHigh

Infrastructure RiskModerate

Aviation RiskSignificant

Geological Composition & Structure

Rock Types

Primary

Dacite

Silica Content

Varied composition

Tectonic Setting

Subduction zone

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

Age & Formation

Epoch

Holocene

Evidence

Evidence Credible

Eruption Statistics & Analysis

Metric	Value	Global Ranking	Significance
Total Recorded Eruptions	Unknown	Low	Moderately active volcano
Maximum VEI	VEI Unknown	Minor	Local impact potential
Recent Activity	Unknown	Historical	Historically active

Monitoring & Alert Status

Monitoring Networks

Japan Meteorological Agency (JMA)

Real-time seismic monitoring

Geological Survey of Japan

Geochemical monitoring

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: 283191
•Evidence: Evidence Credible
•Epoch: Holocene

About the Photo

Hijiori volcano, seen from the E, is a small caldera located NE of the Pleistocene Gassan volcano. The town of Hijiori lies in the left foreground along the banks of two rivers through the caldera floor. The low 2.5-km-wide caldera formed during a large eruption between about 9,500 and 11,000 years ago, accompanied by pyroclastic flows and ashfall that extended to the E and reached the Pacific coast.

Copyrighted photo by Hiroshi Yagi (Japanese Quaternary Volcanoes database, RIODB, http://riodb02.ibase.aist.go.jp/strata/VOL_JP/EN/index.htm and Geol Surv Japan, AIST, http://www.gsj.jp/).