Recent Variation of Global and Regional Correlated Seismicity Rates
摘要
The global correlated seismicity rates from 1990 to 2023 show the temporal variations likely to those from 1990 to 2021, but it is noteworthy that there is rapid high-level period before Tonga-Hunga-Tonga giant eruption. On the other hand, the global correlated seismicity dynamics is characteristic in the structure of the global plate boundaries, which are composed of three arms terminating the global ridge boundary. The simulation of the three-arm slider-block network under external periodic force displays the periodic behavior of correlated displacement and the multi-states dynamics against the periodic external force, thereby suggesting the similarity of the pitchfork bifurcation of global seismicity against the rate of earth rotation. Non-volcanic tremor, low frequency earthquake, and repeating earthquake are represented by rupture process of periodic-arrayed jog (vamp) on the shear slip surface associated with slow to very slow slip events. On the other hand, it is needed that the rapid extrusion process of the subducted huge metamorphic mass in the plate boundary zone is governed by the velocity-independent frictional drag along the large-scale shear zones in the episodic extensional stress environment in the wedge mantle.