Comment on "The 21 August 2017 M d 4.0 Casamicciola Earthquake: First Evidence of Coseismic Normal Surface Faulting at the Ischia Volcanic Island" by

We are writing this comment because many aspects of the analysis presented by Nappi et al. (2018) are debatable. In particular, a major issue is relevant to the conclusion suggested by Nappi et al. (2018) about a seismogenic normal fault with northward dip; this finding is not grounded because the Authors do not really present a causative source model and, above all, their statement is clearly not consistent with the DInSAR, GPS and seismological measurements presented in the manuscript previously published by De Novellis et al. (2018). Moreover, we also report an evident error in the geologic map proposed by Nappi et al. (2018), see Figure 3 of their manuscript.