The   historically   active   Batur   volcano   is   located   at   the   center   of   two   concentric   calderas   NW of   Agung   volcano.   The   outer   10   x   13.5   km   wide   caldera   was   formed   during   eruption   of   the Bali   (or   Ubud)   Ignimbrite   about   29,300   years   ago   and   now   contains   a   caldera   lake   on   its   SE side,   opposite   the   satellitic   cone   of   2152-m-high   Gunung Abang,   the   topographic   high   of   the Batur   complex.   The   inner   6.4   x   9.4   km   wide   caldera   was   formed   about   20,150   years   ago during   eruption   of   the   Gunungkawi   Ignimbrite. The   SE   wall   of   the   inner   caldera   lies   beneath Lake   Batur;   Batur   cone   has   been   constructed   within   the   inner   caldera   to   a   height   above   the outer   caldera   rim.   The   1717-m-high   Batur   stratovolcano   has   produced   vents   over   much   of the   inner   caldera,   but   a   NE-SW   fissure   system   has   localized   the   Batur   I,   II,   and   III   craters along   the   summit   ridge.   Historical   eruptions   have   been   characterized   by   mild-to-moderate explosive   activity   sometimes   accompanied   by   lava   emission.   Basaltic   lava   flows   from   both   summit   and   flank   vents   have   reached   the caldera floor and the shores of Lake Batur in historical time. (Global Volcanism Program)