The manuscript deals with a sinkhole cluster on the sports field of Münsterdorf, a village north of Hamburg in Germany, examined through geophysical surveys and mechanical models. The topic is certainly of interest to Solid Earth.

I have listed in the accompanying file a number of small edits, and requests of clarification on some issues that are not clear to me. Overall, I therefore require moderate revisions and invite the Authors to carefully read my comments on the pdf file. Here, I just summarize the main points where the Authors should make an effort to further improve the quality and clarity of the paper.

Line 33-34: I disagree with what stated. Suffosion sinkholes do not belong to the category of collapse sinkholes but are formed by different processes. Authors are kindly invited to have a look at the classification proposed by Gutierrez et al. (2014), recently revised by Parise (2019, 2022).

References:

Gutierrez F., Parise M., De Waele J. & Jourde H., 2014, A review on natural and human-induced geohazards and impacts in karst. Earth Science Reviews, vol. 138, p. 61-88, doi: 10.1016/j.earscirev.2014.08.002.

Parise M., 2019, Sinkholes. In: White W.B., Culver D.C. & Pipan T. (Eds.), Encyclopedia of Caves. Academic Press, Elsevier, 3rd edition, ISBN ISBN 978-0-12-814124-3, p. 934-942.

Parise M., 2022, Sinkholes, Subsidence and Related Mass Movements. In: Shroder J.J.F. (Ed.), Treatise on Geomorphology, vol. 5. Elsevier, Academic Press, pp. 200–220. https://dx.doi.org/10.1016/B978-0-12-818234- 5.00029-8. ISBN: 9780128182345.

Lines 76-77: it is reported that “In the mines, numerous karst features can be observed, such as dissolutionally-enlarged fissures and bedding planes and small collapse sinkholes”. One figure, with two or more pictures, to show these features and their size could be useful to readers.

Still as regards figures, no photo of the sinkholes is provided. I would appreciate adding one figure with some pictures to show the main characters of the phenomena.

Lines 91-92: about the depth of the water table, it would be interesting to know at what depth it is, and if water fluctuations in response to rainfall occur. Some more information should be provided at this regard.

Lines 125 and following (3.2. Hypotheses): both presented hypothesis start from the presence of an underground void. What if the void was not present, and the sinkholes are not of collapse origin? Is there the possibility of suffusion sinkholes? The lack of photographs of the sinkholes make difficult to understand if this third hypothesis could be true. In any case, why do you suppose the presence of voids for the sinkhole formation?

This is the main problem I see in this article, since it is assumed that a void is present, and the possibility of a different typology of sinkholes is not taken into consideration at all. Authors should clarify the reasons why they consider only the presence of voids (either in the peri-glacial sand or in the chalk), excluding the other possibility.

For all the considerations above, I recommend major revision.

The paper deals with an interesting aspect of the application of geophysical investigations and modelling for the understanding of genesis and the exploration of sinkholes of the locality Münsterdorf. The focus is on the use of results from direct push soundings and geophysical explorations for the numerical modelling of the formation of sinkholes. The publication of the paper is supported in any case, but some minor but substantial changes or additions are required:

Previous geophysical measurements

Various assumptions about the geological structure of the subsurface come from earlier geophysical investigations, which unfortunately only briefly described. A table with the measurements carried out so far with reference to literature should be added.

Forward Modeling

From the reviewer's point of view, two overly simplified model calculations for the detectability of cavities by means of gravimetry and geoelectrics are presented. In addition, the rock physical parameters used must be checked for consistency in the paper. For example, some of the resistivities used for modeling do not match the values given in Table 1. Furthermore, the effect of the described glazial till layers was not taken into account, although these influence the density distribution and resistivity distribution in the subsurface. 

This section should be supplemented by geophysical measurement examples for gravimetry and geoelectrics from the investigation area. If this is not possible, the section can also be omitted.

Drop of the groundwater level as an initial event

The drop of the groundwater surface causes the formation of earth falls. The hypothesis is explained in detail and comprehensibly. However, there is a lack of information on the past and present location of the groundwater surface as well as on the course of the groundwater surface between the study area and the opencast mine. In Figure 11, information on the location and topographical height of the stör river and the opencast mine as well as the distance between the objects must be supplemented to scale. Is a lowering of the groundwater level by several meters away from the opencast mine really realistic and what role does the mentioned fault zone on which the sinkholes are located play?