Proceedings of the 12th International INQUA meeting on paleoseismology, active tectonic and archaeoseismology

Fig. 3: Photogrammetric Analysis. A) Flight Zone. The area selected by the morphological expression of the fault. An important aspect to consider is that the density of vegetation in this area can affect the accuracy of the Digital Elevation Model (DEM). A red line representing seismic line AB was recorded. B) Classification of the point cloud. Obtained through photogrammetric processing using Agisoft Metashape software. Brown dots represent terrain, green dots indicate different levels of vegetation, and red dots indicate built structures such as houses and buildings. Subsequently, the Plotrefa module was used to create a plot of the dromochrones and define the parameters of the a priori model (Fig. 4B). Once the a priori model was obtained, tomographic inversion tests were performed. Octave software was used to confirm the final optimal tomographic model. (Araujo et al., 2023). Using matrix operations, data conversion was performed, facilitating the creation of the convergence plot (Fig. 5B) and the regularization of the L-curve (Fig. 5A). Finally, the Geoplot module was used to visualize the seismic profile. We adjusted the corresponding parameters to optimize the visualization, resulting in a clearer and more detailed representation of the seismic data. Fig. 4: Refraction seismic tomography process. A) Pickwin module. For example, in a shot for a seismic line of the experiment, the source indicates the position of each shot on the distance scale. Distance is plotted on the x-axis, while time is plotted on the y-axis. B) Plotrefa module. Illustrates the initial seismic tomography model with 10 layers, showing velocity variations from 0.3 km/sec at the surface to 2.5 km/sec at a depth of 25 meters over a depth range of 25 meters. The different colored dots represent the location of the geophones.