25 May 2022
Research article | 25 May 2022
Long-term analysis of cryoseismic events and associated ground thermal stress in Adventdalen, Svalbard
Rowan Romeyn et al.
- Final revised paper (published on 25 May 2022)
- Preprint (discussion started on 25 Oct 2021)
Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor |
: Report abuse
RC1: 'Comment on tc-2021-329', Anonymous Referee #1, 15 Nov 2021
- AC1: 'Reply on RC1', Rowan Romeyn, 01 Feb 2022
RC2: 'Comment on tc-2021-329', Babak Ravaji, 13 Dec 2021
- AC2: 'Reply on RC2', Rowan Romeyn, 01 Feb 2022
RC3: 'Comment on tc-2021-329', Anonymous Referee #3, 17 Dec 2021
- AC3: 'Reply on RC3', Rowan Romeyn, 01 Feb 2022
- AC5: 'Reply on RC3 - fix', Rowan Romeyn, 01 Feb 2022
RC4: 'Comment on tc-2021-329', Anonymous Referee #4, 05 Jan 2022
- AC4: 'Reply on RC4', Rowan Romeyn, 01 Feb 2022
Peer review completion
AR: Author's response | RR: Referee report | ED: Editor decision
ED: Reconsider after major revisions (further review by editor and referees) (02 Feb 2022) by Evgeny A. Podolskiy
AR by Rowan Romeyn on behalf of the Authors (17 Feb 2022)  Author's response Author's tracked changes Manuscript
ED: Referee Nomination & Report Request started (21 Feb 2022) by Evgeny A. Podolskiy
RR by Anonymous Referee #1 (10 Mar 2022)
RR by Anonymous Referee #2 (12 Mar 2022)
ED: Publish subject to revisions (further review by editor and referees) (22 Mar 2022) by Evgeny A. Podolskiy
AR by Rowan Romeyn on behalf of the Authors (28 Apr 2022)  Author's response Author's tracked changes Manuscript
ED: Publish as is (02 May 2022) by Evgeny A. Podolskiy
Long term analysis of cryoseismic events and associated ground thermal stress in Adventdalen, Svalbard
by Romeyn et al.
Romeyn et al. analyze 17 years of passive seismic data from the SPITS array (Svalbard) to extract a catalog of short duration seismic events (~1s) with the aim to study freeze processes in the subsurface. They find two event classes where one of them appears to be related to anthropogenic coal mining, and the other one to frost cracking – the targeted cryoseisms. The hypothesis of frost-cracking events is supported by the event locations as well as by modeling of the subsurface stress based on temperature time series from a borehole.
This is an interesting study, which gives valuable insights into the dynamics of a periglacial environment, i.e. into processes that are difficult to observe. The authors use a astonishingly long observation period of high quality seismic array data. Combined with their thermal-stress modeling, they present strong evidence, that most of the detected events are caused by thermal contraction cracking. The manuscript is well written, but I think several aspects, in particular on the nature and location of the frost quakes, remain unclear. Together with some more minor comments, I suggest moderate revisions prior to publication. Below I provide all my comments.
Reference: Wathelet, M., Jongmans, D., Ohrnberger, M., & Bonnefoy-Claudet, S. (2008). Array performances for ambient vibrations on a shallow structure and consequences over Vs inversion. Journal of Seismology, 12(1), 1-19.
Line 27: pressure release → stress release?
Lines 39-40: “These structures form …”. I am having trouble to understand this process, maybe consider rewriting this sentence.
Lines 49-57: What’s the difference between ice wedges and segregation ice. As far as I understand one can broadly distinguish them as vertical and horizontal ice structures in the subsurface, respectively? Consider to add some definition here, if applicable.
Line 61: “… InSAR has used …” → has been used
line 73: “This study was motivated” → is motivated
line 73: sporadic? From the paper it seems there are quite many of these events?
Line 96: Maybe add a reference after matched field processing, that describes the “broadband, coherent” approach? Because that’s the special part in this study, right?
Line 127: So the weather station is measuring the air temperature plus the temperature of the ground in 0.1m depth? Please clarify.
Line 131: What do you mean by “first-pass”?
Lines 137 and following: A bit difficult to follow here – for the STA you take the envelopes and smooth them with a 1s sliding windows and for the LTA you smooth this curve once more with a 20s sliding window? Please clarify and maybe rewrite the text.
Line 180: I think it should be the absolute value of the term after the sum. As is, it would be a complex MFP amplitude. Same for equation (7). Please check.
Line 254-256: So you basically do a forward modeling using the measured temperature time series at a certain depth (and the parameters from Table 1) to calculate the resulting stress at this depth? If so, maybe strengthen this point here.
Line 280: So only less than 100 events were recorded by less than five stations and thus discarded?
Line 293: “are” is missing before “associated”
Line 294: I see that compared to your previous study, nine seismic stations can be considered an array that coarsely samples the spatial domain, but I think this cannot be considered a general statement. Maybe relate this to your previous study.
Line 319: delete “due”, same in line 326.
Line 330, Fig. 6 and especially Fig. 7: Interestingly, the three main source clusters of class I events are centered exactly around three of the array stations. This looks a bit suspicious to me, could this be an artifact in the MFP results, can you comment on this?
Line 341 and following: This relates to a previous comment: To calculate the stress at a certain depth, does only a single temperature time series from this particular depth enter the calculation, or does it also include the vertical temperature gradient? What does the word “combination” in line342 imply?
Line 353: “Figure 9 …” → Figure 9a. It would also be interesting to show the event rate (e.g. events/day) as a line together with the calculated stress in Fig. 9b.
Figure 2: It took me a while to understand what’s actually shown, since this is a continuous time series split into several subfigures. I would either merge the graphs of each row and/or write the year as text into the graphs, to make it easier for the reader.
Figure 3: a) and b) are missing, but are referenced in the text. Also, in the caption, please provide more detail on what is actually shown.
Fig 4: The crosses of the stations are hardly visible in subplots g, h, i
Fig 6: The seasonality is hard to see from the figure. I suggest to give the total number of events shown in each panel e.g. in their titles.
Fig 7b-d: Being non-trained in this, it is difficult for me to spot the boulder producing scarps and solifluction lobes. Consider adding annotations to the images.
Fig 10: Maybe it would be better to show the event detection rate as a line instead of the vertical bars? What is the apparent stress? Please specify.
Fig 11: I think it would be instructive to show only the class I events and again maybe as a line or as bars. You have shown that earlier, that class II events are independent of the thermal stress, so it would be better to focus on your finding that the closeby events are related to the stress.