New page on The Geysers studies

The Geysers represents a unique site for analysis of induced seismicity. This vapor-dominated geothermal field is located about 120 km north of San Francisco where the geothermal power production is performed for more than 50 years. Currently, The Geysers is the world’s largest geothermal field operated by Calpine and spanning an area of around 78km2 with the nominal capacity of 1517 MW. It is also an area of intensive induced seismic activity, with the largest event reaching magnitude 5.0. The seismicity is recorded with an extensive seismic monitoring networks operated by Lawrence Berkeley National Laboratory, and broadband regional network.

The availaibility of high quality data triggered our interest in understanding seismo-mechanical processes in this reservoir. This resulted in a number of publications, that I decided to gather in one place – The Geysers resesarch page.

Paper on Acoustic Emission activity during hydraulic fracturing experiment in Äspö, Sweden

We published a new paper in the Journal of Geophysical Research: Solid Earth related to the hydraulic fracture experiments performed in 2015 in  Äspö Hard Rock Laboratory, Sweden. Here are the highlights:

  • We analyze source characteristics of picoseismicity (moment magnitudes smaller than -3.5!) related to hydraulic stimulations in Äspö Hard Rock Laboratory, Sweden.
  • We show that spatio-temporal seismicity migration is controlled by changes in hydraulic (pressure times volume) energy.
  • We present that total radiated seismic energy is very low with respect to injected volume, and increases with hydraulic energy rate.

The reference:

Kwiatek, G., Martínez-Garzón, P., Plenkers, K., Leonhardt, M., Zang, A., Specht, S., et al. (2018). Insights Into Complex Subdecimeter Fracturing Processes Occurring During a Water Injection Experiment at Depth in Äspö Hard Rock Laboratory, Sweden. Journal of Geophysical Research: Solid Earth, DOI: 10.1029/2017JB014715. [ Article Page ]

Paper on earthquake clustering in hydrothermal reservoirs

We published another paper on induced seismicity, this time related to the clustering properties of induced seismicity observed in a couple of hydrothermal reservoirs. Here is the reference:

Martínez-Garzón, P., I. Zaliapin, Y. Ben-Zion, G. Kwiatek, and M. Bohnhoff (2018). Comparative Study of Earthquake Clustering in Relation to Hydraulic Activities at Geothermal Fields in California. Journal of Geophysical Research: Solid Earth, 123. DOI: 10.1029/2017JB014972 [ Article Page ]

Paper in BSSA on focal mechanism of small earthquakes from the Salton Sea

Stephan Bentz published paper entitled “Sensitivity of Full Moment Tensors to Data Preprocessing and Inversion Parameters: A Case Study from the Salton Sea Geothermal Field”. The paper presents the results of investigation of mechanisms of approximately 80 small seismic events using two full seismic moment tensor inversion routines: the full waveform inversion and hybridMT code. The paper appeared in the Bulletin of Seismological Society of America.


Bentz, Stephan, P. Martínez-Garzón, G. Kwiatek, M. Bohnhoff, and J. Renner (2018). Sensitivity of Full Moment Tensors to Data Preprocessing and Inversion Parameters: A Case Study from the Salton Sea Geothermal Field, Bull. Seismol. Soc. Am. DOI: 10.1785/0120170203.

New presentations on Earthquake Detection limits and Hydraulic fracturing experiment

I added two presentations from SSA Meeting in Reno in 2016, and recent EUROCK conference in Ostrava last year.

Kwiatek, G., P. Martínez-Garzón, K. Plenkers, M. Leonhardt, A. Zang, S. Specht, G. Dresen, and M. Bohnhoff (2017). Insights into subdecimeter fracturing processes occuring during the hydraulic fracture experiment in Äspö HRL, Sweden, in Proceedings of EUROCK conference, Ostrava, Czech Republic.

[ Download PDF document (32.31 MB) ]

Kwiatek, G., and Y. Ben-Zion (2016). Theoretical Limits on Detectability of Small Earthquakes, Seismol. Res. Lett. 87, 510.

[ Download PDF document (3.98 MB) ]