Thermal infrared thermometers deployed ~250 m from Stromboli's active craters can detect thermal emissions during strombolian explosions. Explosions appear as spikes in thermal time series, with variations in the mass erupted during each event revealed by pulses in the time series. During May 2001, Stromboli's NE and SW craters showed consistently different thermal signatures. SW crater events were characterized by long lasting (>10 s), higher amplitude thermal signals with significant fluctuations, whereas the NE crater was characterized by short (<5 s), impulsive, lower amplitude signatures. The two craters showed well-correlated variations in thermal amplitude evolving over periods of several hours and providing strong evidence for linkage of the craters to a common feeding system affected by cyclic processes that drive steady variations in the style of emission.