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

I N T R O D U C T I O N As we approach the 50th anniversary of the M 7.5 February 4, 1976 Guatemala earthquake, a new collaborative research effort was initiated to investigate the Motagua fault which ruptured in the earthquake. With a surface-wave magnitude of 7.5, the destructive 1976 earthquake that occurred at 3:03 a.m. caused structural damage to buildings in cities and collapse of entire villages of adobe houses resulting in 23,000 deaths (Espinosa, 1976). The earthquake ruptured the left-lateral, strike-slip Motagua fault along the tectonic boundary separating the North American and Caribbean plates. The ground rupture extended for an identified length of 230 km in the Motagua Valley and west into the mountains north of Guatemala City (Plafker, 1976). The fault rupture may have extended farther but was obscured to the west by earthquake-triggered landslides and to the east by swamps and vegetation (Fig. 1). Fig. 1: DEM of Guatemala showing the left-lateral, strike-slip surface rupture of the Motagua fault in the 1976 earthquake. Six sites where LiDAR data were collected are labelled.