Grimsnes

Volcanic field in Iceland

Last Eruption: -3500

Key Facts

Elevation

200 m (656 ft)

Type

Volcanic field

Location

64.050°, -20.883°

Region

Iceland Neovolcanic Rift Volcanic Province

Rock Type

Basalt / Picro-Basalt

Tectonic Setting

Rift zone

Location

Loading map...

Overview

Grímsnes is a relatively small volcanic system located SE of Thingvallavatn lake. It is displaced about 15-20 km to the east of the other en-echelon group of volcanic fields of the Western Volcanic Zone extending across the Reykjanes Peninsula. Its lava flows cover 54 km2 and were erupted from a group of 11 fissures that produced a series of NE-SW-trending crater rows.

The eruptions of its basaltic lavas were considered to have been restricted to a relatively short interval between about 6,500 and 5,500 years ago, but radiocarbon dating showed that some of the lava flows were emplaced between about 7,400 and 8,900 years ago.

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

Rift zone

Continental rift or intraplate setting with varied eruptive styles.

Age & Formation

Epoch

Holocene

Evidence

Eruption Dated

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	5526 years ago	Historical	Historically active

Monitoring & Alert Status

Monitoring Networks

Global Volcanism Program

International eruption database

Current Status

Normal

No recent activity. Routine monitoring continues.

Nearby Volcanoes in Atlantic Ocean Volcanic Regions

Regional Volcanic Activity

The Atlantic Ocean 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: 371060
•Evidence: Eruption Dated
•Epoch: Holocene

About the Photo

A small pond about 60 x 100 m fills the bottom of the Kerid crater at the northern end of the Tjarnarhólar crater row in the Grímsnes volcanic system. The crater is elliptical in shape, 180 x 280 m. The Seyðishólar and Kerhóll cinder cones, visible in the background to the north, were active about 9,500 and 7,050 years ago respectively. Seyðishólar is the only Holocene eruption recognized to have had tephra dispersal outside of the volcanic field.

Photo by Lee Siebert, 2008 (Smithsonian Institution).