We examine two closely located earthquakes in Japan that had identical moment magnitudes M_w but significantly different energy magnitudes M_e. We use teleseismic data from the Global Seismograph Network and strong-motion data from the National Research Institute for Earth Science and Disaster Prevention's K-Net to analyze the 19 October 1996 Kyushu earthquake (M_w 6.7, M_e 6.6) and the 6 October 2000 Tottori earthquake (M_w 6.7, M_e 7.4). To obtain regional estimates of radiated energy E_S we apply a spectral technique to regional (<200 km) waveforms that are dominated by S and Lg waves. For the thrust-fault Kyushu earthquake, we estimate an average regional attenuation Q(f) 230f^0:65. For the strike-slip Tottori earthquake, the average regional attenuation is Q(f) 180f^0:6. These attenuation functions are similar to those derived from studies of both California and Japan earthquakes. The regional estimate of E_S for the Kyushu earthquake, 3:8 ?? 10¹⁴ J, is significantly smaller than that for the Tottori earthquake, E_S 1:3 ?? 10¹⁵ J. These estimates correspond well with the teleseismic estimates of 3:9 ?? 10¹⁴ J and 1:8 ?? 10¹⁵ J, respectively. The apparent stress (T_a = ??E_s/M₀ with ?? equal to rigidity) for the Kyushu earthquake is 4 times smaller than the apparent stress for the Tottori earthquake. In terms of the fault maturity model, the significantly greater release of energy by the strike-slip Tottori earthquake can be related to strong deformation in an immature intraplate setting. The relatively lower energy release of the thrust-fault Kyushu earthquake can be related to rupture on mature faults at a subduction environment. The consistence between teleseismic and regional estimates of E_S is particularly significant as teleseismic data for computing E_S are routinely available for all large earthquakes whereas often there are no near-field data.