Near‐field ground‐motion data are available in semi‐real time either from modern strong‐motion or continuous Global Positioning System (GPS) networks, allowing robust solutions for earthquake source parameters, which are useful for rapid disaster assessment and early warning. These wide applications require the ground‐motion data to cover a very broad frequency band that, however, is usually not available. This paper presents a case study on the 2011 M_w 9.0 Tohoku earthquake, showing how the ground‐motion information from geodetic and seismic instrumentations is complementary, and suggesting the joint use of both types of data, particularly when the network coverage is sparse. First the strong‐motion records from the two Japanese networks, K‐NET and KiK‐Net, are analyzed using an automatic empirical baseline correction tool. The static coseismic displacement data are obtained by double integration and then used to derive the permanent slip distribution on the earthquake fault. Comparisons with the corresponding GPS‐based solutions yield a quantitative estimation of uncertainties of the empirical baseline correction. Furthermore, a dozen nearby GPS and strong‐motion station pairs are selected to demonstrate that the information in their time series agrees with each other. Finally, methods for combining both types of ground‐motion observation systems are discussed, and the wide applicability of this approach is highlighted.

A hybrid method is proposed to calculate complete synthetic seismograms based on a spherically symmetric and self-gravitating Earth with a multi-layered structure of atmosphere, ocean, mantle, liquid core and solid core. For large wavelengths, a numerical scheme is used to solve the geodynamic boundary-value problem without any approximation on the deformation and gravity coupling. With decreasing wavelength, the gravity effect on the deformation becomes negligible and the analytical propagator scheme can be used. Many useful approaches are used to overcome the numerical problems that may arise in both analytical and numerical schemes. Some of these approaches have been established in the seismological community and the others are developed for the first time. Based on the stable and efficient hybrid algorithm, an all-in-one code QSSP is implemented to cover the complete spectrum of seismological interests. The performance of the code is demonstrated by various tests including the curvature effect on teleseismic body and surface waves, the appearance of multiple reflected, teleseismic core phases, the gravity effect on long period surface waves and free oscillations, the simulation of near-field displacement seismograms with the static offset, the coupling of tsunami and infrasound waves, and free oscillations of the solid Earth, the atmosphere and the ocean. QSSP is open source software that can be used as a stand-alone FORTRAN code or may be applied in combination with a Python toolbox to calculate and handle Green's function databases for efficient coding of source inversion problems.

The slip rate and its spatial variations of the Kunlun fault (KLF) play important roles in the tectonic evolution of the northeastern Tibetan Plateau. Here the slip rate of the Tuosuo Lake (TL) segment of the KLF, which remains controversial from various geological observations, is investigated with a dense Global Positioning System observation profile. With a viscoelastic earthquake‐cycle deformation model, the slip rate of the TL segment is estimated to be 5.5 ± 0.7 mm/a, in comparison with an overestimated value of 9.2 ± 1.1 mm/a from an elastic model. Combined with previous results, we infer that the slip rate of the KLF likely decreases gradually from the TL segment toward the eastern tip, rather than remaining uniform along the fault or decreasing rapidly within the easternmost 150 km. The estimated lower crust viscosity (~10¹⁸ Pa · s) agrees with values inferred from postseismic studies, which suggests a weak ductile lower crust in this region.

Summary. Differential radar interferometry provided high-quality near-field deformation data for the 2003 Bam earthquake and therefore strong constraints on it