Drone-borne magnetic investigations of the Bárðarbunga and Askja volcanic fissure systems, Northeast Iceland
Abstract
The Bárðarbunga and Askja volcanoes are active volcanic systems located about 55km apart along the Eastern and Northern Volcanic Zones in northeastern Iceland. The Bárðarbunga volcano, being a subglacial stratovolcano beneath the Vatnajökull ice cap, is part of a volcanic system with a fissure swarm that reaches more than 50 km northeast from the central volcano, interdigitating with the fissure swarm of the Askja system. Active fissures within the Bárðarbunga and Askja systems are monitored by seismic stations, providing information on current unrest. Thus, the crustal deformation and seismicity relating to the dike intrusion that fed the fissure eruptions in 2014-2015, in the Holuhraun lava field between Bárðarbunga and Askja, were well-documented. However, getting a detailed understanding of the prehistoric activity in the fissure swarms between the two systems is less straightforward and understood although such information may shed light on future eruption scenarios as well as how the two volcanic systems may have (co)developed. Detailed mapping of the subsurface magnetic signal may provide such information given that dykes become strongly magnetized upon cooling. Based on geological insight of the Holuhraun lava field and years of development and testing of drone-borne magnetic sensor systems, we carried out a three-weeks survey campaign north of Vatnajökull with the purpose of mapping the magnetic signature of the two volcanic fissure systems, as well as the recent-most Holuhraun dike intrusion. A large portion of the survey area is a low-relief landscape dominated by dynamic geomorphologic processes. Two magnetic sensor systems were deployed: a lightweight single sensor magnetometer bird towed by a DJI M210 drone and a double-sensor gradiometer bird towed by a DJI Wind 4 drone. Eight adjacent surveys were flown in the area, adding up to 650 line-km of data and a total area covered of 7 x 15km. In addition, four ground magnetic surveys (20 km) were conducted across the volcanic systems, and rock samples were collected for ground truth rock magnetism analysis of the airborne magnetic signal. We present a combined interpretation of the survey data, providing new information about the active and inactive parts of the Bárðarbunga and Askja fissure swarms immediately to the north of Vatnajökull.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMGP0120004D
- Keywords:
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- 1545 Spatial variations: all harmonics and anomalies;
- GEOMAGNETISM AND PALEOMAGNETISM;
- 1550 Spatial variations attributed to seafloor spreading;
- GEOMAGNETISM AND PALEOMAGNETISM;
- 3005 Marine magnetics and paleomagnetics;
- MARINE GEOLOGY AND GEOPHYSICS;
- 3006 Marine electromagnetics;
- MARINE GEOLOGY AND GEOPHYSICS