Abstract
Improved Seismic Monitoring with OBS Deployment in the Arctic: A Pilot Study from Offshore Western Svalbard
The mid‐ocean ridge system is the main source of earthquakes within the Arctic region. The
earthquakes are recorded on the permanent land‐based stations in the region, although smaller
earthquakes remain undetected. In this study, we make use of three Ocean Bottom Seismographs
(OBSs) that were deployed offshore western Svalbard, along the spreading ridges. The OBS arrival
times were used to relocate the regional seismicity, using a Bayesian approach, which resulted in a
significant improvement with tighter clustering around the spreading ridge. We also extended the
regional magnitude scales for the northern Atlantic region for OBSs, by computing site correction
terms. Besides location and magnitude improvement, the OBS network was able to detect hundreds of
earthquakes, mostly with magnitude below Mw 3, including a swarm activity at the Molloy Deep. Our
offshore observations provide further evidence of a low‐velocity anomaly offshore Svalbard, at the
northern tip of Knipovich ridge that was previously seen in full‐waveform inversion. We conclude that
even a single permanent OBS near the ridge would make a significant difference to earthquake
catalogs and their interpretation.
Dahl-Jensen T , Gibbons S , Jeddi Z , Ottemöller L , Rezaei S , Sørensen M , Strømme M ,
Voss P
University of Bergen, Bergen, Norway
Norwegian Geotechnical Institute, Oslo, Norway
Geological Survey of Denmark and Greenland, GEUS, Copenhagen, Denmark
The mid‐ocean ridge system is the main source of earthquakes within the Arctic region. The
earthquakes are recorded on the permanent land‐based stations in the region, although smaller
earthquakes remain undetected. In this study, we make use of three Ocean Bottom Seismographs
(OBSs) that were deployed offshore western Svalbard, along the spreading ridges. The OBS arrival
times were used to relocate the regional seismicity, using a Bayesian approach, which resulted in a
significant improvement with tighter clustering around the spreading ridge. We also extended the
regional magnitude scales for the northern Atlantic region for OBSs, by computing site correction
terms. Besides location and magnitude improvement, the OBS network was able to detect hundreds of
earthquakes, mostly with magnitude below Mw 3, including a swarm activity at the Molloy Deep. Our
offshore observations provide further evidence of a low‐velocity anomaly offshore Svalbard, at the
northern tip of Knipovich ridge that was previously seen in full‐waveform inversion. We conclude that
even a single permanent OBS near the ridge would make a significant difference to earthquake
catalogs and their interpretation.
Dahl-Jensen T , Gibbons S , Jeddi Z , Ottemöller L , Rezaei S , Sørensen M , Strømme M ,
Voss P
University of Bergen, Bergen, Norway
Norwegian Geotechnical Institute, Oslo, Norway
Geological Survey of Denmark and Greenland, GEUS, Copenhagen, Denmark
| Original language | English |
|---|---|
| Publication status | Published - 20 Sept 2021 |
| Event | 37th General Assembly of the European Seismological Commission - ESC - Online / Greece Duration: 19 Sept 2021 → 24 Sept 2021 https://www.erasmus.gr/microsites/1193/virtual-platform-guide |
Conference
| Conference | 37th General Assembly of the European Seismological Commission - ESC |
|---|---|
| Period | 19/09/21 → 24/09/21 |
| Internet address |
Programme Area
- Programme Area 3: Energy Resources