Focos seismicos del Archipielago Filipino (1900): the Manila Observatory's seismic zonation of the Philippines

A treatise printed in 1900 by the Jesuits of the Manila Observatory that divides the Philippines into three seismic zones by parallels of latitude, names the epicentral foci in each, tabulates their tremors, and prints a colour map of them. It reasons from Lyell and Lapparent, defines epicentre as the "foco aparente", and reaches across the Pacific for its example of an earthquake that arrived in complete silence: Riobamba, 4 February 1797.