Agustín Udías is Emeritus Professor at the Universidad Complutense, Madrid, Spain. He is the author of many papers about seismicity, seismotectonics of the Azores-Gibraltar, and the physics of seismic sources, and has also written several textbooks. Professor Udías has served as Editor-in-Chief of Física de la Tierra and the Journal of Seismology, and as the Vice-President of the European Seismological Commission. He is a member of the Accademia Europeae, the Seismological Society of America, the American Geophysical Union, amongst other societies, and is a Fellow of the Royal Astronomical Society.