Estimated Moho Temperature from Observed Heat Flow and Comparison with P-Wave Velocity in the East Sea, Korea

Abstract:

We have estimated temperatures at the Moho surface by employing a published empirical relationship of Perry et al’s work (JGR, doi:10.1029/2005JB003921) to the observed heat flow measurements in the East Sea (Sea of Japan), Korea. We assumed in our computation that the parameter values are all the same although the Perry et al’s relationship between crustal thickness and heat flows to compute Moho temperature was derived for the Canadian Shield. For the heat flow data, we used the published global heat flow data (http://www.heatflow.und.edu) augmented with some recent heat flow measurements from Korea, and the LLN3_G3Dv3 for P-wave tomography model (JGR, doi:10.1029/2012JB009525). Preliminary results do not show a significant correlation between the computed Moho temperature and the P-wave velocity model perhaps due to uncertainty in the parameter values used in the computation as well as the empirical relation. An empirical relationship between the observed heat flow and the Moho temperature for the Canadian shield might be different for a backarec basin area like the East Sea, Korea. However, we noted that there exists a moderate negative correlation between the total crustal thickness and heat flow - less heat flows with increasing crustal thickness with a relation of Heat_Flow (mW/m²) = 205 – 18.3 * Crustal_Thickness (km). The modeled Moho temperature displays a trend of higher values (900^o K -1400^o K) from Japan toward the beneath of Yamato Basin and Rise in the NW direction, and beneath the Ulleung Basin area. Another higher Moho temperature (>1000^o K) contour band is observed in the area north of Japan Basin, approximately centered along the 139.5^o E.