29: Global volcanic activity report for January 19, 2013

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 Santiaguito Dome Complex (Santa Maria). A few larger magnitude volcanic earthquakes punctuate an otherwise slowly decreasing trend in seismicity at San Cristobal volcano (Nicaragua) (station CRIN) today. Volcanic tremor amplitude continues to be unstable at Masaya volcano (station MASN), and frequent, low-amplitude volcanic earthquakes continue to plague Concepcion volcano (station CONN). An episode of larger magnitude volcano-tectonic earthquakes also affected Nevado Del Ruiz volcano (Colombia) (station OLLZ) late yesterday.  Numerous low-amplitude volcanic earthquakes and occasional periods of volcanic tremor continue at the volcano.  Numerous small seismic events continue at nearby Machin volcano (station CIMA) as well. The tremor-like signal late in the record at Machin is due to cultural noise, not the volcano. Strong degassing continues at Reventador volcano (Ecuador) (station CONE), accompanied by abundant low-frequency seismicity, including volcanic tremors. Over 1100 small volcanic earthquakes, along with low-level volcanic tremors have occurred during the past 24 hours at Copahue volcano (Chile-Argentina border).  Weather obscures any surface activity accompanying the seismicity. –Earthquake Report