两种GPS反演方法在日本西南与菲律宾板块交界处的应用与比较

APPLICATION AND COMPARISON OF TWO KINDS OF GPS INVERSE METHODS ON BORDER LAND BETWEEN PHILIPPINE SEA PLATE AND SOUTHWEST JAPAN

采用日本西南地区与菲律宾板块边界的GPS连续观测数据（1997-01～1999-12），利用Hori反演解析方法，得到了板块交界面上的滑动缺损矢量分布。结果表明：滑动缺损矢量大小和方向都与菲律宾板块的运动速度吻合，最大值为7cm／a，50％耦合分布都集中在10～30km之间。用同样的观测数据和板块交界结构的数据，利用Yabuki-Matu＇ura反演方法进行了计算，并将计算结果与Hori方法的结果进行比较发现，由于两者不同的解析过程和不同的约束条件，日本东部对中部地区的冲撞效应在计算结果上出现了不同。通过比较和分析认为Hori方法能够比较客观和直接地反映观测数据的信息，而更适用于类似日本西南部观测数据比较密集的地区。

The Hori and Yabuki-Matu＇ ura inverse methods are used to estimate the distribution of inter-seismic slip deficit on the border land between Philippine Sea plate and the southwest Japan with GPS data from Jan. , 1997 to Dec. ,1999. The estimated results show that maximum slip rate is about 7 cm/a, which is consistent with the Philippine Sea plate convergence rate. The 50% contribution of strong coupling is confined to the depths of 10 - 30 km. By compring the two results it can be seen that there are some different effects caused by the collision between eastern and central Japan, because of different analytic process and constrain condition. It can be concluded that Hori inverse method is more applicable and impersonal to estimate slip distribution in the area with dense observation networks, such as the southwest Japan.