Introductory paper of the 8th International Symposium on Andean Geodynamics (ISAG) special number

The International Symposium on Andean Geodynamics (ISAG) is an international conference that was held, on average, every 3–4 years in different European cities between 1990 (Grenoble) and 2008 (Nice). These symposia usually offer an opportunity for researchers from Latin American countries and Europe as well as other countries to review the state of knowledge in geosciences on the Andes. After a long period without an edition, the 8th ISAG was organized for the first time in a Latin American country, Ecuador, from 24th to 26th September 2019. The organizing committee led by Pablo Samaniego relied heavily on the Instituto Geofísico of the Escuela Politécnica Nacional (IG-EPN) and the Institut de Recherche pour le Développement (IRD), in particular through its office in Quito, and through the Laboratoire Mixte International in France and Ecuador: “Seismes et Volcans dans les Andes du Nord” (LMI-SVAN); and the French Embassy in Ecuador. Field trips in tectonics, seismotectonics and volcanology at emblematic sites in Ecuador were organized by researchers from the IRD (Isterre and LMV), the Institut de Radio Protection Nucléaire (IRSN), IG-EPN and the University of Geneva. Four invited speakers gave presentations: Peter Molnar (University of Boulder) on the mechanisms of the Andes uplift, Suzanne Kay (Cornell University) on its magmatism, Victor Ramos (University of Buenos Aires) on the scientific approaches developed through time for the Andean orogeny and Eric Calais (Ecole Normale Supérieure de Paris) on the difficulty of dialog between seismic risk specialists and the authorities in Haiti. The symposium also provided an opportunity for more than 250 participants to meet, with more than 80 oral presentations and over 150 posters. As a result of this conference, the Editor of the Journal of South American Earth Sciences proposed to the organizing committee to publish a special issue on the contours of these presentations. Following the peer review process, 19 papers are published in this special issue. These manuscripts reflect the various disciplinary fields, geophysics and deep imaging, tectonics, volcanism, geomorphology and seismic hazard, from the local scale to the Andes as a whole. Not surprisingly, a higher density of works is found in Ecuador and the northern Andes (Figure 1). As this collection of articles reflects the outlines of a symposium and not a specific scientific question, our aim here is not to develop a synthesis of current knowledge on the Andes. We therefore present these articles in sequence, by discipline, although this categorization may appear subjective since some articles are multidisciplinary.