P-wave velocity (Vp) and S-wave velocity (Vs) of Ichino-megata mafic xenoliths, northeast (NE) Japan, were measured simultaneously under the subsolidus conditions. We obtain non-linea r velocity-temperature correlation for all rock studied. Significant Vp and Vs decreases at higher temperatures are probably attributed to thermal cracking and/or phase transition of plagioclas e and/or amphibole.
