Options
Optimization of local scale seismic networks applied to geothermal fields. The case of the Acoculco caldera, Mexico
Language
English
Obiettivo Specifico
2V. Struttura e sistema di alimentazione dei vulcani
Status
Published
JCR Journal
JCR Journal
Peer review journal
Yes
Title of the book
Issue/vol(year)
/119 (2022)
ISSN
1873-0647
Publisher
Elsevier
Pages (printed)
103995
Issued date
November 2022
Subjects
04. Solid Earth
Abstract
The exploitation of a geothermal field can be accompanied by both natural and induced
seismicity. Hence the installation of a seismic network suitable for locating also low
magnitude earthquakes is of great interest for geothermal development, especially for
monitoring the activity related to the injection or production.
Here we propose an improvement of the D-OPTIMAL algorithm (Tramelli et al., 2013) that tries and find optimal station positions minimizing the volume of the error ellipsoid of the event location using the D-criterion. In this version, we introduced the possibility to account for several prior information that is generally available when instrumenting a monitoring site permanently or temporarily. The a priori parameters introduced are: i) three-dimensional seismic velocity models, ii) seismic noise levels, iii) topographic gradient, and iv) H/V ratio
values. The last three parameters are introduced in the station position 24 selection using aweighting system.
We applied the methodology to the Acoculco geothermal field (Mexico) where an injection test was planned and executed in 2021. The comparison between the network defined usingthe standard approach and this updated version shows the importance of introducing a prioriinformation during the selection of the network. Installation sites resulted better distributed on the region, resulting in an overall increase of the sensitivity, and in a decreasing of the error location estimation in the target region. The methodology presented here is easy to apply to other study cases such as active volcanoes, anthropogenic activities, or whatever other study at local scale.
seismicity. Hence the installation of a seismic network suitable for locating also low
magnitude earthquakes is of great interest for geothermal development, especially for
monitoring the activity related to the injection or production.
Here we propose an improvement of the D-OPTIMAL algorithm (Tramelli et al., 2013) that tries and find optimal station positions minimizing the volume of the error ellipsoid of the event location using the D-criterion. In this version, we introduced the possibility to account for several prior information that is generally available when instrumenting a monitoring site permanently or temporarily. The a priori parameters introduced are: i) three-dimensional seismic velocity models, ii) seismic noise levels, iii) topographic gradient, and iv) H/V ratio
values. The last three parameters are introduced in the station position 24 selection using aweighting system.
We applied the methodology to the Acoculco geothermal field (Mexico) where an injection test was planned and executed in 2021. The comparison between the network defined usingthe standard approach and this updated version shows the importance of introducing a prioriinformation during the selection of the network. Installation sites resulted better distributed on the region, resulting in an overall increase of the sensitivity, and in a decreasing of the error location estimation in the target region. The methodology presented here is easy to apply to other study cases such as active volcanoes, anthropogenic activities, or whatever other study at local scale.
Type
article