the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 15 Sep 2025
Deciphering the Crustal Structure of the Lerma Valley (NW Argentina): A Multi-Method Seismic Investigation
Abstract. We investigated the crustal structure beneath the Lerma Valley in northwestern Argentina using data from a local seismic network deployed between 2017 and 2018. This geologically complex transition zone between the Eastern Cordillera and the Sierras Subandinas is characterized by moderate to high seismicity (INPRES, 2024), yet remains largely understudied despite its strategic location within the Andean orogen (Jordan et al., 1983; Allmendinger et al., 1997). Its passive orogenic setting and evidence of inherited structures (Ramos, 2008; Mon and Salfity, 1995; Kley and Monaldi, 2002) make it a natural laboratory for exploring intraplate deformation and foreland basin evolution (Pérez et al., 2016; Tassara et al., 2018). We combined local and teleseismic receiver functions with ambient noise tomography (ANT), jointly inverting Rayleigh wave phase velocities to obtain 1D shear-wave velocity profiles. The results reveal a stratified crust with four main discontinuities at ∼ 53–43, 35–30, 10–8, and 1.5–1.2 km, corresponding to the Moho, mid- and lower-crustal boundaries, and the base of the sedimentary basin. A southward-dipping Moho is evident from CCP migration and T-component phase shifts. Velocity profiles also show a north–south contrast: lower velocities (1–2.5 km/s) in the south indicate thicker, less consolidated sediments, while the north exhibits more competent crust (up to 3.5 km/s). The final model comprises five layers, including three sedimentary and two crystalline crustal units. We also introduced a layer-dependent κ correction, revealing a trend from 1.65 at the Moho to 2 in upper layers. These results provide new geophysical constraints on the crustal architecture and tectonic evolution of this underexplored Andean region.
- Preprint
(8322 KB) - Metadata XML
- BibTeX
- EndNote
Status: final response (author comments only)
-
RC1: 'Comment on egusphere-2025-2979', Anonymous Referee #1, 17 Nov 2025
-
AC1: 'Reply on RC1', Emilio José Marcelo Criado-Sutti, 18 Nov 2025
Dear Referee,
We would like to express our profound gratitude for your insightful comments. During the process of compilation, there were some issues that led to mislocation of some figures and references without spaces. It is possible to address these issues presently, in addition to those associated with the results and discussion sections. The proposed changes will be executed, and the text and figures will be refined.
We would like to express our gratitude once more.
There is no need to be concerned about the delayed response.
Citation: https://doi.org/10.5194/egusphere-2025-2979-AC1
-
AC1: 'Reply on RC1', Emilio José Marcelo Criado-Sutti, 18 Nov 2025
-
RC2: 'Comment on egusphere-2025-2979', Franck Audemard, 12 Dec 2025
Dear Authors
Please, pay attention to my corrections, comments, observations, amendements and suggestions provided along an annotated version of your original PDF submission.
I wish you success and prompt resubmission of your contribution.
Franck A. AUDEMARD M.
-
AC2: 'Reply on RC2', Emilio José Marcelo Criado-Sutti, 15 Dec 2025
Dear Franck,
Thank you very much for your comments and suggestions. As mentioned previously, some of the minor issues were due to a problem in the compilation process. All other points have now been carefully addressed in the revised version, particularly in Figure 1 and in the Results and Discussion sections.
We greatly appreciate the time and effort you have devoted to reviewing our work, as well as your constructive feedback. The updated version of the manuscript will be ready next week.
Kind regards,
EmilioCitation: https://doi.org/10.5194/egusphere-2025-2979-AC2
-
AC2: 'Reply on RC2', Emilio José Marcelo Criado-Sutti, 15 Dec 2025
-
EC1: 'Comment on egusphere-2025-2979', Irene Bianchi, 30 Dec 2025
Dear Authors,
thank you for your interesting study. Before sending the manuscript to next step I would like to add few comments to those raised by the authors.
As a general comment, I would like to ask to check the consistency between the interpreted models across the manuscript, as the mid-crustal layer seems to be not always present.
A final figure summarizing the results is needed to illustrate the interpreted structures in the area.
More context for the local RF needs to be given: where was this technique used before and which constraints was it able to give?
Figure 4: the local RF for the 3Hz panels should be shown up to 5 s, otherwise the wiggles are not readable.
Line 30: replace "underscores" with "highlights"
Line 114: replace "Ps phase" with "Ps phase and its multiples"
Line 119: (like Ps) in brackets
Section 3.2.2 For the local RF it is not clear which catalogues has been used. Is there a table that I missed? Depth and distance are important parameters for such kind of applications. Please add a sentence that illustrates the events used at about L 135, and add a table of the events (stating depth and distance from the stations).
Section 3.2.5 The section describes an interesting way for the estimate of K. Anyway a direct comparison between the "normally" estimated K and the adjusted K needs to be shown together with the eventual obtained improvement; the significance of the improvement needs to be discussed.
L 246 the sensitivity tests need to be shown in the Appendix.
The RF (local and tele) at all stations need to be shown (as appendix)
The H-k results at all stations for all layers and for both techniques need to be shown.
Line 268-269: no, we cannot see how the local RF are constraining the H and k. This is missing in the manuscript, therefore the H-k results at all stations for all layers and for both techniques need to be shown.
Figure 5: The meaning of this figure is not clear, and needs to be explained.
Line 283: 7-% of the error means that the parameter is not constrained, how can these results be interpreted?
Figure 8: the discontinuities need to be marked, otherwise it is not clear what the authors are discussing.
Figure 9: The discontinuities need to be marked, e.g. local and tele RF show different polarities for the same depths, how are these differences explained?Please address carefully all comments raised by the authors and by myself. In particular, the concerns regarding the significance of the methods used, the consistency of the results throughout the manuscript, and the demonstration of the robustness of both the data and the findings are essential. If these issues are not adequately resolved, they may lead to the rejection of the manuscript.
Citation: https://doi.org/10.5194/egusphere-2025-2979-EC1
Viewed
| HTML | XML | Total | BibTeX | EndNote | |
|---|---|---|---|---|---|
| 849 | 139 | 24 | 1,012 | 31 | 39 |
- HTML: 849
- PDF: 139
- XML: 24
- Total: 1,012
- BibTeX: 31
- EndNote: 39
Viewed (geographical distribution)
| Country | # | Views | % |
|---|
| Total: | 0 |
| HTML: | 0 |
| PDF: | 0 |
| XML: | 0 |
- 1
In the manuscript titled 'Deciphering the Crustal Structure of the Lerma Valley (NW Argentina): A Multi-Method Seismic Investigation' presented by Criado-Sutti et al., the velocity structure of the Lerma Valley (north-western Argentina) is studied using two different data sets: local and teleseismic receiver functions and ambient noise tomography. These data were inverted to obtain 1D shear wave velocity models beneath each seismic station, providing constraints on the velocity structure down to a depth of 80 km. In addition, group and phase velocity maps between 2-5 seconds of period were calculated, adding information on the crustal structure of the studied area. However, although the data and methods section is well described and discursive, the results and discussion section is not as clear, often lacking references to figures or introducing them later (or never referring to them, as in Figure 9), creating considerable difficulty for the reader. For example, Figure 9 is never mentioned in the text, and it was only at the end of the manuscript that I was able to understand comments and interpretations included in the text that were previously unclear.
Furthermore, the English is often incorrect. For this reason, I am attaching my revisions in PDF format. I am attaching them as I made them step by step and only noticed Figure 9 at the end, so I ask you to take this into account when reading my comments.
Therefore, although the work is valid in terms of the data and methods applied in a previously unconstrained area of study and is certainly of geodynamic/geological interest, I suggest the manuscript required major revisions. I ask the authors to be clear when presenting the results and to insert the figures correctly. All other comments can be found in the PDF. In the PDF, I have also suggested to modify some Figures (Fig. 2, Table 3, Figure 6).
Finally, I would suggest performing further tests on the cross-correlations shown in the graph in Figure 6. I suggest checking whether applying other bandpass filters with different ranges (ex 0.1-0.5 Hz) can improve the energy of the plotted waveforms.
I hope I have been helpful and apologise for the delay.