Fault reactivation by gas injection at an underground gas storage off the east coast of Spain
Item
Title (Dublin Core)
Fault reactivation by gas injection at an underground gas storage off the east coast of Spain
Description (Dublin Core)
<p>During September–October of 2013 an intense swarm of
earthquakes occurred off the east coast of Spain associated with the
injection of the base gas in an offshore underground gas storage. Two weeks
after the end of the injection operations, three moderate-sized earthquakes
(<span class="inline-formula"><i>M</i><sub>w</sub></span> 4.0–4.1) occurred near the storage. These events were widely felt by
the nearby population, leading to the indefinite shut-down of the facility.
Here we investigate the source parameters (focal depth and mechanism) of the
largest earthquakes in the sequence in order to identify the faults
reactivated by the gas injection and to help understand the processes that
caused the earthquakes. Our waveform modeling results indicate that the
largest earthquakes occurred at depths of 6–8 <span class="inline-formula">km</span> beneath the sea floor,
significantly deeper than the injection depth (<span class="inline-formula">∼1800</span> <span class="inline-formula">m</span>).
Although we cannot undoubtedly discriminate the fault plane from the two
nodal planes of the mechanisms, most evidence seems to favor a NW–SE-striking fault plane. We propose that the gas injection reactivated faults
in the Paleozoic basement, with regional orientation possibly inherited from
the opening of the Valencia Trough.</p>
earthquakes occurred off the east coast of Spain associated with the
injection of the base gas in an offshore underground gas storage. Two weeks
after the end of the injection operations, three moderate-sized earthquakes
(<span class="inline-formula"><i>M</i><sub>w</sub></span> 4.0–4.1) occurred near the storage. These events were widely felt by
the nearby population, leading to the indefinite shut-down of the facility.
Here we investigate the source parameters (focal depth and mechanism) of the
largest earthquakes in the sequence in order to identify the faults
reactivated by the gas injection and to help understand the processes that
caused the earthquakes. Our waveform modeling results indicate that the
largest earthquakes occurred at depths of 6–8 <span class="inline-formula">km</span> beneath the sea floor,
significantly deeper than the injection depth (<span class="inline-formula">∼1800</span> <span class="inline-formula">m</span>).
Although we cannot undoubtedly discriminate the fault plane from the two
nodal planes of the mechanisms, most evidence seems to favor a NW–SE-striking fault plane. We propose that the gas injection reactivated faults
in the Paleozoic basement, with regional orientation possibly inherited from
the opening of the Valencia Trough.</p>
Creator (Dublin Core)
A. Villaseñor
R. B. Herrmann
B. Gaite
A. Ugalde
Subject (Dublin Core)
Geology
QE1-996.5
Stratigraphy
QE640-699
Publisher (Dublin Core)
Copernicus Publications
Date (Dublin Core)
2020-01-01T00:00:00Z
Type (Dublin Core)
article
Identifier (Dublin Core)
10.5194/se-11-63-2020
1869-9510
1869-9529
https://doaj.org/article/cbc64c133f4b404ba51ca3ba50dc3f54
Source (Dublin Core)
Solid Earth, Vol 11, Pp 63-74 (2020)
Language (Dublin Core)
EN
Relation (Dublin Core)
https://www.solid-earth.net/11/63/2020/se-11-63-2020.pdf
https://doaj.org/toc/1869-9510
https://doaj.org/toc/1869-9529
Provenance (Dublin Core)
Journal Licence: CC BY