Title Text:The USGS operates a really neat email/SMS earthquake notification service (earthquake.usgs.gov/ens/) that allows fine-grained control of notifications. Origin:https://xkcd.com/723/ https://www.explainxkcd.com/wiki/index.php/723:_Seismic_Waves 网络时代的地震预警 根据惠更斯-菲涅尔原理，（帖子）波前上的每一点都可看作新的次（帖子）波源…… https://songshuhui.net/archives/48993 围绕Twitter用户的一个刻板印象是，他们更关心的是广播他们当… Read more