## 3 Results and Discussion
### Deformation Maps  
Seismic activity in the coastal zone of the Biobio region is a recurrent phenomenon, but to our knowledge, it is not known if it is the main cause of deformation in the area. In this research, deformation was identified to establish its relationship with the seismic component in the coast of the Biobio region. The total displacement field estimated by PSI for the period spanning from January to December 2017 is displayed in Figure 6. The colored pixels represent those scatterers interpolated that are found to be coherent and selected as PS. To reduce the influence of a single scatterer, we average the displacements of the PS inside this area. After the phase noise estimate, the overall noise was reduced, and PS points filtered. Several stable-phase pixels are 1,334,951. Weed standard deviation = 1, and bad PS pixels (too much noise or ground contributions). The 'Unwrapprefilter_flag' parameter was kept in 'y' to improve the accuracy of the unwrapping. Positive values indicate that the deformation approached the satellite in the direction of the line-of-sight (LOS); negative values denote that deformation in the LOS motion turned aside, away from the satellite. The monthly maps show the uplift and subsidence in the area, represented by red and blue colors, respectively, with a pixel of 0.2\({}^{\circ}\). The month of May registered the highest range of displacement for the area with values of 40 mm and \(-\)24 mm. On the other hand, July presented values between 24 mm and \(-\)16 mm. It is important to note that both months have a maximum magnitude of 5.8 Mww recorded. Comparing the location between the two epicenters (Figure 3), the earthquake referring to the month of May is located in the continent (\(-\)37.345\({}^{\circ}\) S, \(-\)71.783\({}^{\circ}\) W) and the earthquake referring to the month of July is located in the sea (\(-\)37.345\({}^{\circ}\) S, \(-\)73.361\({}^{\circ}\) W) [50]. The seismic wave has different behaviors depending on the propagation material, and water wave propagation in ocean seismology still represents a challenge for researchers [66]. Geology and soil types (solid materials) are factors to be considered during the investigation of seismic wave propagation [67]. Another reason why July may not show such a high displacement range when compared to May is that this month's image was used as a master during processing. In addition, it is observed that during 7 months of the year, there are values of \(-\)24 mm. Figure 5: Number of earthquakes monthly for the year 2017. The upper part of the graph represents the distribution of quantity, while the right side represents the distribution of the seismic frequency by magnitude according to the USGS classification. It can be observed in Figure 6 the distribution of magnitudes of the earthquakes recorded for 2017, by month. It also shows the distribution of the monthly quantity and magnitudes frequency, classified according to Table 1. February is the month with the highest monthly number, registering a total of 25 daily earthquakes, and June has the lowest number with 1 earthquake for the entire month. When looking at the magnitudes, it is possible to perceive that all months, except June, presented micro, minor, slight, and moderate earthquakes. The highest frequency of earthquakes is between 3.0 Mw and 4.0 Mw, and then between 4.0 Mw and 5.0 Mw. May and July showed the highest magnitudes when compared to the other months. Evaluating the deformation data, it is possible to perceive that May presents the highest value of positive deformation (40 mm), and the highest value of negative deformation (40 mm). Figure 6: Monthly deformation maps for the year 2017.  
and November has the lowest value (20 mm). December has the highest negative maximum. July, August, and October have the lowest negative maxima. January and May have deformation ranges (0 mm and 16 mm, respectively) different from the other months that remained constants (8 mm).