Evidence of Surface Rupture Associated With Historical Earthquakes in the Lower Tagus Valley, Portugal. Implications for Seismic Hazard in the Greater Lisbon Area

The Lower Tagus Valley Fault, Portugal, has long been associated with the damaging earthquakes that affected Greater Lisbon Area in historical times. These include a poorly documented earthquake occurred 1344, relatively well-documented 1531 earthquake, and most recent M6.0 1909 earthquake. In this work, we use 0.5 m resolution LiDAR-based digital elevation model cm surface based on UAV photogrammetry to accurately locate fault scarps northernmost portion of western strand select sites perform paleoseimolological investigations. paleoseismological geochronological analysis performed Alviela trench site document activity last 3000 years, including two during We ground motion scenarios for 20 km, 40 60 km ruptures site. fields obtained are agreement macroseismic intensity data available implying magnitude range M6.8–7.4. However, degree deformation preserved suggests value closer lower bound. level observed (IX) is than modeled intensities all considered could be related particularly high vulnerability building stock.