Using High-frequency GPS To Study The Characteristics Of Surface Deformation During Earthquakes

High frequency GPS receiver for continuous observation of the hardware performance continues to improve,combining with high-efficiency and high-precision GPS data process software,makes GPS provides an important supplementary function for seismology which records velocity or acceleration,the 1-HZ GPS receiver has become GPS seismology which monitors the ground deformation in real time.Based on this background,using TRACK for data processing,the basic theories on 1-HZ GPS data processing was studied: a study of the linear combination of GPS measurements,ambiguity resolution in TRACK,cycle slip detection and repair method,and using TRACK to calculate the measured 1-HZ data GPS of San Simeon earthquake.Analyzes the different characteristics of noise in coordinate time series.On account of the multipath error and common-mode error in time series,we adopt the improved sidereal filter and PCA space filtering methods to remove in order to improve the precision of positioning result.Taking the timing sequence of P401 station as an example,the two filtering steps are introduced in detail.Through the power spectrum methods analysis,it is found that the improved sidereal filtering can effectively improve the positioning accuracy in the low frequency domain.The PCA obtained of Alaska earthquake near field 1-HZ GPS sites of the first three principal components of the vector space,results showed that the first principal component of the vector space model is very smooth,uniform space,the first principal component of coordinate sequence components(East?North?Up)contribution rates were 80.68%,83.92% and 76.49% respectively.Therefore,in this paper,the first principal component is used to calculate the common-mode error.Summarizes the whole process of calculating high frequency GPS data by TRACK,including data preparation,data solution and filter processing.On this basis,the characteristics of dynamic crustal deformation in the near field and far field are studied by using 1-HZ GPS monitoring data from several stations in Alaska seismic area,and according to the displacement time series of GPS site to estimate the arrival time of seismic waves,which were retrieved from the epicenter of the Alaska earthquake(-149.253 W,56.094N),and The difference from the results released by USGS is 12.395 km.Based on the GPS observation data of several stations in the Kaikoura earthquake in New Zealand,the GAMIT/GLOBK software is used to obtain the co-seismic displacement and the complex ground motion sequence.The results of static data processing show that the surface deformation caused by earthquakes occurred mainly in the northeastern part of the South Island and the southern part of the North Island,and from the Kaikoura to the capital of Wellington between the plate as a whole to the northeast of the uplift movement,the largest co-seismic displacement occurred near the CMBL station.The dynamic high frequency GPS data processing showed that the strong earthquake caused the permanent deformation of the northeast direction,and the each stations had different levels of vibration and it is not only associated with epicenter distance but also earthquake rupture propagation directivity.In order to verify the effectiveness of 1-HZ GPS in monitoring kinematic deformation during the earthquake,we choose MKBS seismic station as a reference which was near to the PAEK GPS station,we find good agreement between 1-HZ GPS kinematic displacement time series and velocity records from MKBS integrated to displacement time histories.