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Preliminary Insight Into Volcanic and Tectonic Controls on Crustal Deformation Near Ljósufjöll, Snæfellsnes Peninsula, West Iceland

Description: 

The interplay between volcanoes and tectonics are critical for understanding crustal dynamics and the ongoing Reykjanes Peninsula (RP), Iceland eruptions (2021-present) and graben forming events there provide key insight to this. The Snæfellsnes Volcanic Zone (SVZ) is off-rift and ~100 km to the north of the RP. Although the geochemistry and petrography of the SVZ is known, little is known about the structural framework or tectonic setting. We used a combination of remote sensing, combined with fit-for-purpose drone photography that we modelled using structure from motion (SfM) techniques to develop high resolution (~10 cm) digital elevation models (DEMs) there were a base for geological, geomorphic, and structural mapping, combined with field observations. We identified a major transtensional strike slip fault, striking N135°E and down to the Northeast with a major vertical component (from 4 to 12 m). There is evidence of significant strike-slip displacements including rivers, gulleys and lava flows. We observed recently active extensional fissures showing mode one opening and these fissures end at a “young” late-Holocene cone which shows a structural control of the volcanism here.

SVZ seismic activity in the last few decades was negligible. However since 2021 a greater number of small earthquakes (up to Mw 3.4) occurred along the southern section of the SVZ. Seismicity is up to 20 km. While this is not a sign of an impending eruption, it is an indicator that the SVZ is perhaps being influenced by new magma movement, that shallows over time, which is likely an indication of a future eruption, thus by the time of SSA 2025, it would not be surprising if an eruption had started there. Because of the large fault area and deep seismogenic zone, potentially large earthquakes up to Mw 7+ could be possible based on the preliminary results we show here. These findings contribute to a better understanding of the interaction between volcanic and tectonic processes on SVZ, offering useful insights into crustal deformation mechanisms in oblique rift zones and associated seismic and volcanic hazards.

Session: The Landscape Record of Earthquakes and Faulting [Poster]

Type: Poster

Date: 4/16/2025

Presentation Time: 08:00 AM (local time)

Presenting Author: Elijah

Student Presenter: Yes

Invited Presentation: 

Poster Number: 9

Authors