## 3 Results and Discussion  
### Low/Medium Intensity Seismic Range  
Figure 3a shows the relevant seismic activity in the study area during the 2006-2017 years. Considering this period, the area has several 2023 daily earthquakes. Seismic activity is concentrated offshore. It is important to note that the area that shows the highest concentration of earthquakes is close to geological faults, for example, in the Arauco peninsula. The highest percentage of earthquakes had magnitudes between 2.0 and 4.9 with 93.03% in total on the Richter scale. Magnitudes between 5.0 and 5.9 (moderate) occurred in 6.18%, while those greater than 5.9 (strong) on the Richter scale occurred in 0.79% of the cases. Therefore, it is possible to suggest that the studied area is characterized by seismic events of micro, minor, and slight magnitude. The highest seismicity was found in 2010 and was due to the 27F event (Mw 8.8) (Figure 3b).  
Figure 3: **(a)** Daily seismic activity for the year 2006–2017 and **(b)** number of low and medium seismic events (\(2.0\leq\text{M}\leq 5.9\)) accumulated per year, observed within the study area during the 2006–2019 years. In red circles are represented the seismic events of higher magnitude that occurred in 2017.  
Figure 4 shows the hot spot patterns of earthquake occurrence based on kernel density analysis. The complete data set (Figure 4) showed the presence of a large cluster offshore of Concepcion Bay; however, it is also possible to observe that all cities that make up the study area are located within the zone with the highest and very highest density of daily earthquakes, represented by orange and red colors.  
Although the north of the country was identified with a higher concentration of earthquakes with magnitudes greater than 5.0 Richter in the last 10 years, specifically in the coastal area of the Tarapaca region and in the high plateau area of the Antofagasta region [65], the central zone of Chile, between 30\({}^{\circ}\) S and 35\({}^{\circ}\) S, is a very active seismic zone with a great diversity of subduction earthquakes and has evidenced the most catastrophic events occurring in the country and the world. Therefore, a priority task today is to develop Chile's capabilities and competencies for the study of earthquakes, using new technologies and signals obtained from satellites/radar and GIS.  
Figure 5 shows a monthly distribution of seismic events classified by magnitude during the year 2017. It also shows the distribution of magnitude frequency classified according to Table 1. Particularly, for the year 2017, a total of 148 daily earthquakes were recorded (taking as references the cities investigated), with magnitudes from 2.7 MI to 5.8 Mww. Evaluating this period, February was identified as the month with the highest number of earthquakes, registering a total of 25 daily earthquakes. June has the lowest number with 1 earthquake for the entire period. When looking at the magnitudes, it is possible to perceive that all months, except June, presented micro, minor, slight, and moderate earthquakes. The months with the highest seismological magnitude (5.8) were May and July (showed in red circles in Figure 3). Thus, we can say that the period was characterized by events with magnitudes between 3 and 4, classified as being of minor intensity.  
Figure 4: Daily seismic activity density (kernel density) in the study area during the 2006–2017 years. Geological faults are represented by red lines.