FORECAST FOR NEAR-FAULT GROUND MOTION FIELD AT INTERSECTION EARLY QUATERNARY FAULT ZONE: TAKING ZAOZHUANG NEW CITY AS AN EXAMPLE

Near-fault ground motion field distribution not only provides more abundant seismic inputs, but also can be used as reference for the seismic design and land use planning. In some areas of relatively weak seismic activity, earthquakes tend to occur at the location of the intersection of two early Quaternary faults. The prediction of the near-fault ground motion field distribution at the location of the intersection of two early Quaternary faults has practical significance. As an example,the nearfault ground motion distribution at intersection early Quaternary fault zone of Zaozhuang new City was predicted when a setting earthquake occurred.The high-frequency and low-frequency ground motions were calculated respectively, and were composed to broad-frequency ground motion.1-D equivalent linearization method was used to calculate the broad-frequency ground motion time histories of some special local sites according to survey data. The PGA distribution and the corresponding response spectra of the target region are got according to the ground motion time histories when the design earthquake occurs. The forecasting result has the basic characteristics of near-fault ground motion,and matches the current basic understanding of the ground motion near the fault.