This electronic supplement contains annotations for select earthquakes with references and two tables. The annotations summarize labeled events in the catalog up to 1999 and events of societal importance thereafter. Table S1 provides the following information for each labeled event: column Date refers to the date of an earthquake in local time. For some earthquakes, where sufficient intensity data exist, we approximate the epicentral location (columns Longitude and Latitude). The number of observations (column Number of Observations) corresponds to the number of intensity reports listed in Table S2 of this electronic supplement for a particular earthquake. A geographic region label is defined for some earthquakes and is listed in column Location. This column serves as a reference column to groups of intensity observations in Table S2. Table S2 provides a listing of all of the intensity data in our study.