Revealing 60 years of earthquake swarms in the Southern Red Sea, Afar and the Gulf of Aden
Revealing 60 years of earthquake swarms in the Southern Red Sea, Afar and the Gulf of Aden
Earthquake swarms occur sporadically at divergent plate boundaries but their recurrence over multiple decades and relation to magmatic spreading activity remain poorly understood. Here we study more than 100 earthquake swarms over a 60-year period in the southern Red Sea, Afar, and Gulf of Aden region. We first compiled an earthquake-swarm catalogue by integrating reexamined global and local earthquake catalogues from 1960 to 2017. This yielded 134 earthquake swarms that mainly cluster in 19 different areas in the study region, showing that in most cases swarms recur every few decades in the same area. The swarms exhibit a range of earthquake magnitudes and often include multiple M3 to M5 events with some swarms having occasional larger earthquakes over M6, primarily in southern Afar. Many of the earthquake swarms were clearly associated with rifting events, consisting of magmatic intrusions, surface faulting, and in some cases volcanic eruptions. Together, the swarms suggest that extension at these divergent plate boundaries occurs episodically along <100 km long segments, some of which were previously unrecognized. Within the study region, the Gulf of Aden shows the most frequent swarm activity, followed by Afar and then the southern Red Sea. The results show that the three areas were subject to an increase of earthquake-swarm activity from 2003 to 2013 in the form of three rifting episodes and at least seven volcanic eruptions. We interpret that the most likely controls on temporal variations in earthquake swarm activity are either temporal variations in magma supply, or rifting-induced stress change that trigger clusters of swarms.
Afar depression, Red Sea—Gulf of Aden, earthquake swarm, rifting and breakup, seismicity analysis, tectonics, volcanism
Ruch, Joel
859ef47c-05b5-4cf7-aa8c-dcd202701862
Keir, Derek
5616f81f-bf1b-4678-a167-3160b5647c65
Passarelli, Luigi
d8b10aa5-c3ae-489a-b79f-4d23b8ecdfec
Di Giacomo, Domenico
9e62d47c-c8eb-4852-9296-12fb6bdf62ba
Ogubazghi, Ghebrebrhan
60a848e2-bee8-44dd-a3d3-46f4b76d3f78
Jonsson, Sigurjon
439149c2-e718-4255-8884-f169c88d772d
16 August 2021
Ruch, Joel
859ef47c-05b5-4cf7-aa8c-dcd202701862
Keir, Derek
5616f81f-bf1b-4678-a167-3160b5647c65
Passarelli, Luigi
d8b10aa5-c3ae-489a-b79f-4d23b8ecdfec
Di Giacomo, Domenico
9e62d47c-c8eb-4852-9296-12fb6bdf62ba
Ogubazghi, Ghebrebrhan
60a848e2-bee8-44dd-a3d3-46f4b76d3f78
Jonsson, Sigurjon
439149c2-e718-4255-8884-f169c88d772d
Ruch, Joel, Keir, Derek, Passarelli, Luigi, Di Giacomo, Domenico, Ogubazghi, Ghebrebrhan and Jonsson, Sigurjon
(2021)
Revealing 60 years of earthquake swarms in the Southern Red Sea, Afar and the Gulf of Aden.
Frontiers in Earth Science, 9, [664673].
(doi:10.3389/feart.2021.664673).
Abstract
Earthquake swarms occur sporadically at divergent plate boundaries but their recurrence over multiple decades and relation to magmatic spreading activity remain poorly understood. Here we study more than 100 earthquake swarms over a 60-year period in the southern Red Sea, Afar, and Gulf of Aden region. We first compiled an earthquake-swarm catalogue by integrating reexamined global and local earthquake catalogues from 1960 to 2017. This yielded 134 earthquake swarms that mainly cluster in 19 different areas in the study region, showing that in most cases swarms recur every few decades in the same area. The swarms exhibit a range of earthquake magnitudes and often include multiple M3 to M5 events with some swarms having occasional larger earthquakes over M6, primarily in southern Afar. Many of the earthquake swarms were clearly associated with rifting events, consisting of magmatic intrusions, surface faulting, and in some cases volcanic eruptions. Together, the swarms suggest that extension at these divergent plate boundaries occurs episodically along <100 km long segments, some of which were previously unrecognized. Within the study region, the Gulf of Aden shows the most frequent swarm activity, followed by Afar and then the southern Red Sea. The results show that the three areas were subject to an increase of earthquake-swarm activity from 2003 to 2013 in the form of three rifting episodes and at least seven volcanic eruptions. We interpret that the most likely controls on temporal variations in earthquake swarm activity are either temporal variations in magma supply, or rifting-induced stress change that trigger clusters of swarms.
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Published date: 16 August 2021
Additional Information:
Funding Information:
This research was supported by King Abdullah University of Science and Technology (KAUST), under award number OSR-2015-CRG4-2643, and by the Swiss National Science Foundation, grant PP00P2_176869 JR. In addition, DK was supported by NERC grant NE/L013932 and by MiUR through PRIN grant 2017P9AT72 and LP was supported by NEWTON-g project, Grant Agreement No 801221.
Publisher Copyright:
© Copyright © 2021 Ruch, Keir, Passarelli, Di Giacomo, Ogubazghi and Jónsson.
Keywords:
Afar depression, Red Sea—Gulf of Aden, earthquake swarm, rifting and breakup, seismicity analysis, tectonics, volcanism
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Local EPrints ID: 451204
URI: http://eprints.soton.ac.uk/id/eprint/451204
PURE UUID: f898658f-a206-4dd1-93e1-f5a274377160
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Date deposited: 14 Sep 2021 16:35
Last modified: 17 Mar 2024 03:24
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Contributors
Author:
Joel Ruch
Author:
Luigi Passarelli
Author:
Domenico Di Giacomo
Author:
Ghebrebrhan Ogubazghi
Author:
Sigurjon Jonsson
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