Very-long-period (VLP) pulses with period of 6--7s, displaying similar waveforms, were identified in 1998 from broadband seismographs around the summit crater. These pulses accompanied most of multiphase (MP) earthquakes, a type of long-period event locally defined at Merapi Volcano. Source mechanisms for several VLP pulses were examined by applying moment tensor inversion to the waveform data. Solutions were consistent with a crack striking ~70¿ and dipping ~50¿ SW, 100m under the active dome, suggest pressurized gas transport involving accumulation and sudden release of 10--60 m3 of gas in the crack over a 6s interval.