A5003350223- earthquake and tectonic studies
- Seismic Waves and Analysis
- Seismic Imaging and Inversion Techniques
- High-pressure geophysics and materials
- Earthquake Detection and Analysis
- Geological and Geochemical Analysis
- Geophysical Methods and Applications
- Seismology and Earthquake Studies
- Hydraulic Fracturing and Reservoir Analysis
- Electromagnetic Simulation and Numerical Methods
- Drilling and Well Engineering
- Astro and Planetary Science
- Image and Signal Denoising Methods
- Geophysics and Sensor Technology
- Meteorological Phenomena and Simulations
- Planetary Science and Exploration
- Geology and Paleoclimatology Research
- Underwater Acoustics Research
- Medical Imaging Techniques and Applications
- Geological and Geophysical Studies
- Electromagnetic Scattering and Analysis
- Solar and Space Plasma Dynamics
- Advanced Numerical Methods in Computational Mathematics
- Numerical methods for differential equations
- Ultrasonics and Acoustic Wave Propagation
Chinese Academy of Sciences
2015-2024
Institute of Geology and Geophysics
2015-2024
University of Chinese Academy of Sciences
2019
Instituto de Gastroenterologia de Goiânia
2018
Institute of Tibetan Plateau Research
2005-2010
Minzu University of China
2010
Institute of Information Engineering
2009-2010
Center for Excellence in Tibetan Plateau Earth Sciences
2010
China Earthquake Administration
2010
Naval University of Engineering
2009
Abstract The seismological observation system in China achieved rapid development during the last five years. Data Management Center (DMC) of Earthquake Network (CENC) Administration (CEA) now receives and archives waveform data from more than 1000 permanent seismic stations around real time. For operational, backup, security considerations, DMC at Institute Geophysics (IGP), CEA was established end 2007. IGPDMC is capable receiving processing continuous time China. Currently, management...
High-resolution image and waveform inversion of small-scale targets requires the handling high-frequency seismic wavefields. However, conventional finite-difference (FD) methods have strong numerical dispersions in presence components. To reduce these dispersions, we optimized constant coefficients FD operator by maximizing wavenumber coverage within a given error limitation. We set up three general criteria to enhance convergence algorithm optimization effort. selected limitation be 0.0001,...
Abstract Arrival times of seismic phases contribute substantially to the study inner working Earth. Despite great advances in data collection, usage arrival is still insufficient because overload manual picking tasks for human experts. In this work we employ a deep‐learning method (PickNet) automatically pick much more P and S wave local earthquakes with accuracy close that by experts, which can be used directly determine tomography. A large number high‐quality obtained model may greatly...
Significance After the Apollo and Luna missions, which were flown about 40 years ago, Moon was explored only from orbit. In addition, no samples returned young high-FeO TiO 2 mare basalt in northern Imbrium basin. Such are important to understand formation evolution of Procellarum KREEP [potassium (K), rare earth elements (REE), phosphorus (P)] terrain, a key terrain highly enriched radioactive nuclides. The Chang’e-3 mission carried out first situ analyses chemical mineral compositions...
Conventional explicit finite-difference methods have difficulties in handling high-frequency components due to strong numerical dispersions. One can reduce the dispersions by optimizing constant coefficients of operator. Different from traditional optimized schemes that use 2-norm and least squares, we propose construct objective functions using maximum norm solve simulated annealing algorithm. Both theoretical analyses experiments show our scheme is superior with regard following three...
Abstract The continuous convergence between the Indian and Eurasian plates caused massive lithospheric deformation in Tibetan Plateau led to excessive crustal material escaping through its southeastern margin. However, mechanisms that accommodate materials whether they intrude into Indochina Peninsula are continually under debate. Seismic Lg waves mostly propagate within crust waveguide with an amplitude decay is sensitive properties, such as temperature, partial melting, fracture....
Absorbing boundary conditions are necessary in numerical simulation for reducing the artificial reflections from model boundaries. In this paper, we overview most important and typical absorbing developed throughout history. We first derive wave equations of similar methods unified forms; then, compare their performance via theoretical analyses experiments. The Higdon condition is shown to be best one among three main that based on a one-way equation. Clayton Engquist special case but has...
Abstract Earthquake detection and phase picking play a fundamental role in studying seismic hazards the Earth’s interior. Many deep‐learning‐based methods, including state‐of‐the‐art model called Transformer (EqT), have made considerable progress. However, processing of low signal‐to‐noise ratio (SNR) seismograms remains challenge. Here, we present pair‐input deep‐learning Siamese (S‐EqT), which achieves good performance on SNR using latent information black box pre‐trained EqT array. We...
Abstract As the largest basin on Mars, Utopia Planitia has both experienced and recorded variations of Martian palaeoclimate. Layered subsurface structures have been identified by ground-penetrating radar in southern but lateral subsurface, potentially linked to palaeoclimatic evolution, not investigated. Here we report frequency-variation patterns Zhurong reflections interpret them as buried polygonal terrain below a depth 35 m. Sixteen wedges were within ∼1.2 km distance, suggesting wide...
Abstract The rupture history of the 20 April 2013 M w 6.6 Lushan (China) earthquake is constrained by inverting waveforms local strong motion, teleseismic broadband body waves, and long‐period surface waves. This ruptured a blind thrust fault oriented N210°E (along Longmenshan zone) dipping 40° to NW. inverted slip distribution heterogeneous, dominated patch with roughly right triangular shape, which spans depth range 5–20 km accounts for two thirds total seismic moment (8.9 × 10 18 N m)....
  A typical triple junction in Colombia is critical for understanding the plate convergence and coupling among South American subducting Nazca Caribbean plates (González et al., 2023). However, locating this challenging due to complex geodynamic evolution uncertainty boundaries. Magmatic arc activity has been diverse discontinuous varying subduction angles, resulting blocks with distinct rheological properties thermal structures (Lagardère Vargas, 2021). Seismic Lg...
The eastern margin of the Tibetan Plateau is an area with youngest uplift, strongest deformation, and frequent occurrence large earthquakes. Seismic velocity can constrain lithosphere's rheological strength crustal flow distribution, allowing deformation to be explored for crust upper mantle. However, seismic related rock composition reflects rock's elastic behavior. As a direct anelastic observation deep temperature strength, attenuation decrease multiplicity geodynamic interpretation. We...
The Alaskan mainland overlies the subducting Pacific plate and Yakutat microplate as they subduct beneath southern margin of North American plate. South-central Alaska features massive volcanoes different types, including intraplate volcanoes, Aleutian arc a group densely clustered called Wrangell volcanic field (WVF). How Denali gap (DVG) formed why are remain vigorously debated. Investigating crustal thermal structure can be crucial for understanding subsurface magmatic activity. Seismic...
Abstract Understanding the heterogeneity within a subducting slab is essential for elucidating its rheological properties, which can significantly affect subduction dynamics. Despite importance, fine structure of has remained largely enigmatic due to limited resolution seismic tomography. Here, we utilize deep learning approach, PickNet, collect comprehensive data set arrival‐times first P and S waves from local earthquakes in Northeast Japan. This enables determination high‐resolution ()...
Expressions for displacements on the surface of a layered half-space due to point force are given in terms generalized reflection and transmission coefficient matrices (Kennett, 1980) discrete wavenumber summation method (Bouchon, 1981). The Bouchon with complex frequencies yields accurate near-field dynamic static solutions. The algorithm is extended include simultaneous evaluation multiple sources at different depths. This feature same as Olson's finite element Fourier Bessel code (DWFE)...
We investigate the regional seismic signature of 9 October 2006 North Korean nuclear test. Broadband data for test and a group earthquakes close to site were obtained between December 2000 No- vember 2006. Epicentral distances from stations are 371 1153 km. first use these events calibrate Lg-wave magnitude in network. Then network is used calculate mbLg �� 3:93 Ko- rean explosion. Using modified fully coupled magnitude-yield relation, yield estimated be 0.48 kt. Because large uncertainties...
We investigate regional variations in the Lg ‐wave quality factor ( Q ) Northeast China and its vicinity with a tomographic method. Digital seismic data recorded at 20 broadband stations from 125 events are used to extract spectra. Tomographic inversions independently conducted 58 discrete frequencies distributed log evenly between 0.05 10.0 Hz. simultaneously invert for distribution source spectra individual without using any priori assumption about frequency dependence of model function....
Explicit finite-difference (FD) schemes are widely used in the seismic exploration field due to their simplicity implementation and low computational cost. However, they suffer from strong artifacts caused by using coarse grids for high-frequency applications. The optimization of constant coefficients is popular reducing spatial dispersions, but current methods could not guarantee that bandwidth tolerable dispersion error widest. We have applied Remez exchange algorithm optimize explicit FD...
Through analysis of the Rayleigh wave and Love empirical Green's functions recovered from cross-correlation seismic ambient noise, we image radial anisotropy shear velocity structure beneath southern Tibet central Himalaya. Dense ray path coverage 22 broadband stations deployed by Himalayan Nepal Seismic Experiment project provides unprecedented opportunity to resolve spatial distribution within crust Himalaya Tibet. In shallow subsurface, obtained results indicate significant with negative...
Abstract Seismology plays an important role in characterizing potential underground nuclear tests. Using broad-band digital seismic data from Northeast China, South Korea and Japan, we investigated the properties of recent event occurred North on 2016 January 6. a relative location method choosing previous 2006 explosion as master event, was located within Korean test site, with its epicentre at latitude 41.3003°N longitude 129.0678°E, approximately 900 m north 500 west 2013 February 12....
We collect nine vertical component broadband seismograms from the 25 May 2009 North Korean nuclear explosion for a regional seismic network in which eight stations also recorded 9 October 2006 test. Comparing observed waveforms and spectra two events, we estimate that amplitudes of records second event are approximately five times those first one. Additionally, use 599 82 events on between December 1995 to calibrate Lg ‐wave magnitude. The calibrated is used calculate body‐wave magnitude m...
Lian-Feng Zhao,1,2 Xiao-Bi Xie,2 Wei-Min Wang,3 Jin-Hai Zhang1 and Zhen-Xing Yao1 1Key Laboratory of the Earth’s Deep Interior, Institute Geology Geophysics, Chinese Academy Sciences, Beijing, China. E-mail: zhaolf@mail.iggcas.ac.cn 2Institute Geophysics Planetary Physics, University California, Santa Cruz, CA 95064, USA 3Key Continental Collision Plateau Uplift, Tibetan Research, China