Local Earthquake Tomography at Los Humeros Geothermal Field (Mexico). Issue 12 (7th December 2020)

• Record Type: Journal Article
• Authors: Toledo, T.; Gaucher, E.; Jousset, P.; Jentsch, A.; Haberland, C.; Maurer, H.; Krawczyk, C.; Calò, M.; Figueroa, A.
• Is Part Of: Journal of geophysical research. Volume 125:Issue 12(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-12-07
• Subjects: Los Humeros -- geothermal exploration -- induced and local seismicity -- P and S velocity structure; Geomagnetism -- Periodicals; Geochemistry -- Periodicals; Geophysics -- Periodicals; Earth sciences -- Periodicals; 551.1
• DOI: 10.1029/2020JB020390
• Languages: English
• ISSNs: 2169-9313

Abstract

Abstract: A passive seismic experiment using 25 broadband and 20 short‐period stations was conducted between September 2017 and September 2018 at Los Humeros geothermal field, an important natural laboratory for superhot geothermal systems in Mexico. From the recorded local seismicity, we derive a minimum 1‐D velocity model and obtain 3‐D V p and V p / V s structures of Los Humeros. We improved the classical local earthquake tomography by using a postprocessing statistical approach. Several inversions were computed and averaged to reduce artifacts introduced by the model parametrization and to increase the resolution of the investigated region. Finally, the resulting V p and V p / V s structures and associated seismicity were integrated with newly acquired geophysical and petrophysical data for comprehensive interpretation. The recorded seismicity is mainly grouped in three clusters, two of which seem directly related to exploitation activities. By combining new laboratory measurements and existing well data with our V p model, we estimate possible geological unit boundaries. One large intrusion‐like body in the V p model, together with neighboring high V p / V s anomalies, hints at a region of active resurgence or uplift due to the intrusion of new magma at the northern portion of the geothermal field. We interpret high V p / V s features as fluid bearing regions potentially favorable for further geothermal exploitation. Deep reaching permeable faults cutting the reservoir unit could explain fluid flow from a deeper local heat source in the area. Key Points: High‐quality earthquake data were collected to image the V p and V p / V s models for the first time at Los Humeros geothermal field (Mexico) Inversions were performed by extending the classical earthquake tomography using a postprocessing statistical approach Geological unit boundaries and fluid and gas bearing zones were interpreted considering new geological, geophysical, and petrophysical data