January 19, 2013 – GEOLOGY – A low-level earthquake swarm continues beneath Mammoth Mountain volcano (CA) (station MMS), with a M1.3 event recorded earlier today. Dilatometer data from instruments located within Long Valley Caldera show an inflection in trend at the swarm onset on or around 15 January 2013. A series of small explosions (green signals) followed a very subtle increase in volcanic seismicity in the past day at the Colima volcano (Mexico).  Exhalations of gas and ash have increased slightly during the past 24 hours at Popocatepetl volcano. A mixture of wind noise, and small local and larger regional earthquakes dot seismograms at Guatemalan volcanoes Fuego (station FG3), Santa Maria (station STG6) and Pacaya (station PCG) today.  Santa Maria seismograms show the most volcanic activity with occasional increases in tremor tucked within the “noisy” record. Recent MODIS thermal imagery shows the active lava flows descending the flanks of Fuego and the…