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

116 PATA Days 2024 1 2 T H I N T E R N AT I O N A L I N Q U A M E E T I N G O N PA L E O S E I S M O L O G Y , A C T I V E T E C T O N I C S A N D A R C H A E O S E I S M O L O G Y ( PATA ) , O C T O B E R 6 T H - 1 1 T H , 2 0 2 4 , L O S A N D E S , C H I L E K E Y W O R D S Porotoyacu Fault, Seismic activity, Seismic tomography, Cartography, photogrammetry (1) Universidad Regional Amazónica Ikiam, Tena, Napo, Ecuador (2) Earth Sciences and Climate Research Group, Universidad Regional Amazónica Ikiam, Ecuador (3) Geosciences Laboratory, Universidad Regional Amazónica Ikiam, Parroquia Muyuna, Napo, Ecuador *Email: Conteron86@gmail.com Henry Conteron (1) Samira Lluno (1) Oswaldo Guzmán (2) Sebastián Araujo (2) Corina Campos (2) Bryan Valencia (2) Anderson Guamán (3) Juan Villacrés (1) CARTOGRAPHY OF THE POROTOYACU FAULT IN A SOUTHERN SECTION OF THE ECUADORIAN AMAZON A B S T R A C T This study employs aerial photogrammetry followed by seismic tomography to achieve a detailed mapping of the Porotoyacu Fault in the Ecuadorian Amazon. The study area, located south of the fault, covers 0.388 km². Initially, a high-resolution digital elevation model (22 cm/pixel) was used for detailed surface mapping. Subsequently, the fault geometry was identified at depth using seismostratigraphic and structural analysis of a 69-meter seismic profile extending to 25 meters deep. The results reveal that: 1) The fault trace extends in a north-south direction. 2) The Porotoyacu Fault has an inverse geometry with a steep angle near the surface that flattens at depth. And, 3) The slope observed corresponds to the flank of an anticline. I N T R O D U C T I O N Seismicity in Ecuador is controlled by the subduction zone of the Nazca plate with the South American plates and the responsible faults are poorly known (Fig. 1A) (Chunga et al., 2016). Ecuador has approximately 92 active surface faults (Eguez et al., 2003; Costa et al., 2020). These geological structures are part of several fault systems, among which the Napo-Cutucú Fault System stands out. Located in the Eastern Sub-Andean Belt of Ecuador, this fault system represents a geological feature of the region. It is active throughout the northern Amazon region (Bès de Berc, 2003). Within this fault system is the Porotoyacu Fault, an active surface structure. This fault has an approximate extension of 15 km crossing the Tena city, and a transcurrent-inverse kinematics (Fig.