Seismicity during and after stimulation of a 6.1&thinsp;km deep enhanced geothermal system in Helsinki, Finland

Leonhardt, Maria; Kwiatek, Grzegorz; Martínez-Garzón, Patricia; Bohnhoff, Marco; Saarno, Tero; Heikkinen, Pekka; Dresen, Georg

doi:https://doi.org/10.5194/se-12-581-2021

Articles | Volume 12, issue 3

https://doi.org/10.5194/se-12-581-2021

© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/se-12-581-2021

© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 12, issue 3

Research article

|

04 Mar 2021

Research article |

| 04 Mar 2021

Seismicity during and after stimulation of a 6.1 km deep enhanced geothermal system in Helsinki, Finland

Maria Leonhardt, Grzegorz Kwiatek, Patricia Martínez-Garzón, Marco Bohnhoff, Tero Saarno, Pekka Heikkinen, and Georg Dresen

Download

Final revised paper (published on 04 Mar 2021)
Supplement to the final revised paper
Preprint (discussion started on 17 Sep 2020)
Supplement to the preprint

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

- Printer-friendly version

- Supplement

RC1: 'Review of manuscript Seismicity during and after stimulation of a 6.1 km deep Enhanced Geothermal System in Helsinki, Finland', Anonymous Referee #1, 28 Oct 2020
- AC1: 'Response to Anonymous Referee #1', Maria Leonhardt, 14 Dec 2020
RC2: 'Review - seismicity associated with ESG stimulation in Finland', Anonymous Referee #2, 16 Nov 2020
- AC2: 'Response to Anonymous Referee #2', Maria Leonhardt, 14 Dec 2020

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

AR by Maria Leonhardt on behalf of the Authors (21 Dec 2020) Author's response Manuscript

ED: Referee Nomination & Report Request started (23 Dec 2020) by Michal Malinowski

RR by Anonymous Referee #1 (03 Jan 2021)

Suggestions for revision or reasons for rejection

The authors made a good job. I like separating the study to a research paper and data publication. Accordingly, I did not review the data publication, I have only one small question to it.
However, there are still some unclear points that should be addressed before accepting, please see below.

Major points
——————-
Ln 101,102: please indicate the minimum magnitude of the two data sets incl. 5456 and 55707 events. It would be also useful to mention what type of detection/picking was used for the two data sets

Ln 117: ‘A total of 2,958 reprocessed events were located…’: please specify what was the reason for relocation only about 60% of the catalog events: too large RMS, or position too far from the well or something else?

Ln 212: Only the two shallower cluters elongate along SHmax, please be more precise

Ln 214: What do you mean by saying ‘…spans ~700 m depth. This exceeds 215 vertical relocation precision…’? I believe this is not surprising as your estimated relocation precision is 52m (Ln 129).

Ln 219 - 220: The statement ‘The post-injection seismicity … seems to be mostly confined to three isolated clusters, with two of them located on the NW flank of the injection well OTN-3’ is not very clear - I do not see two grey clusters at this position. Possibly you can omit this statament as it does not bring valuable info.

Ln 293: ‘We further analyzed qualitatively the polarity pattern of events with polarities estimated from cross-correlation based technique of Shelly et al. (2016) ..’: It is not clear whether this analysis is also shown in Fig. 8.

Ln 295 - 305: it is not easy to follow this section without illustrating the situation in a plot/table.

Ln 377-382: The stress computations need be better explained. The point is that stress varies with depth and is thus unique for each event. And further, how do you estimate the pore pressure to get effective stress?

Ln 384 - 390: Fig. S5 should be moved to the main part as Fig. 11 and Table S1 as well.

Minor, language
———————-

Ln 279: ‘very different in between families’ - ‘in’ appears superfluous

Ln 280: between three -> among three

Ln 316: ‘The stress inversion of the induced seismic events represents a local reverse faulting regime.’ Stress inversion as a method (correctly Inversion of focal mechanisms for stress) cannot represent a faulting regime. I suggest ‘The stress obtained by focal mechanism inversion represents…’

Ln 386: S5 should read as S6, same for Ln 393

Figures
———-

Fig. 2: To make the caption more informative, please give the number of events shown (2958?)

Fig. 3: Please indicate the profile of the depth section (b) in the map view (a)

Fig. 8: It would be useful to give the number of events for each family also in the caption, better than in the text

Fig. S3: The figure caption is not correct. According to youe reponse 14) the light gray symbols show all events, not those with Mw>=1.

Fig. 10: In the caption you state that ‘A stress ratio of R = 0.53 was used for stress inversion.’ This sounds confusing as R is the result of stress inversion

Data publication
-------------------
In Fig. 5 you show the Gutenberg-Richter distribution of the new catalog. It would be however much more iknformative to show two curves: one for the original catalog and another for the new one. Then one would see at which magnitude levels most new events were detected.

Hide

ED: Publish subject to minor revisions (review by editor) (11 Jan 2021) by Michal Malinowski

AR by Maria Leonhardt on behalf of the Authors (18 Jan 2021) Author's response Author's tracked changes Manuscript

ED: Publish as is (19 Jan 2021) by Michal Malinowski

ED: Publish as is (21 Jan 2021) by CharLotte Krawczyk (Executive editor)

AR by Maria Leonhardt on behalf of the Authors (28 Jan 2021)