Magma, Mountains & Mass Movements: The Dynamic Chilean Arc

This field guide supports an international field excursion traversing the dynamic subduction margin of central Chile from Santiago to Laguna del Maule. Designed for geoscientists and graduate students, the guide explores the interplay among tectonics, magmatism, and surface processes across the Principal and Coastal Cordilleras and the intervening Central Depression. Initial stops along the San Ramón Fault examine active thrust faulting at the urban edge of Santiago, highlighting its seismic hazard and paleoseismic record. The excursion then transitions to the Laguna del Maule volcanic field, one of the most rapidly deforming silicic systems globally. Here, participants investigate postglacial rhyolitic volcanism, active crustal deformation, and fault-controlled magmatic systems. Field stops include trench exposures, fault zone architecture, paleoshorelines deformed by ongoing uplift, and monitoring stations that integrate GPS, InSAR, seismic, and geochemical data. The guide emphasizes the integration of structural, geomorphic, geodetic, and petrologic observations to constrain the evolution of this convergent margin. Throughout, participants are encouraged to consider how arc volcanism, upper-plate faulting, and glacial-interglacial cycles interact to shape landscapes and modulate geohazards. Funded by SZNet through the NSF AccelNet program, this guide supports international collaboration and early-career training in subduction zone science.