Three-dimensional velocity structure models in and around the Kathmandu Valley, Central Nepal

We analyzed observations of microtremors and seismic ground motion to determine the depths of sedimentary interfaces and basement surface in the Kathmandu Valley. The results of these analyses and a reflection survey were combined to produce a data set of seismic depths for sedimentary interfaces an...

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Bibliographic Details
Published inEarth, planets, and space Vol. 76; no. 1; pp. 6 - 11
Main Authors Koketsu, Kazuki, Suzuki, Haruhiko, Guo, Yujia
Format Journal Article
LanguageEnglish
Published Berlin/Heidelberg Springer Berlin Heidelberg 01.12.2024
Springer
Springer Nature B.V
SpringerOpen
Subjects
4. Seismology
Active Tectonics and Seismic Hazards in the Himalayan Region
Airports
Basements
Central Nepal
Datasets
Earth and Environmental Science
Earth movements
Earth Sciences
Earthquakes
Environmental aspects
Fourier transforms
Geology
Geophysics/Geodesy
Gravity
Gravity survey
Ground motion
Kathmandu Valley
Lithosphere
Mechanical properties
Modelling
Observations
Ratios
Regional-scale models
Rivers
S waves
Scale models
Sediments
Seismic survey
Three dimensional models
Valleys
Velocity
Velocity structure
Wave velocity
Nepal
Velocity structure
Gravity survey
Central Nepal
Seismic survey
Kathmandu Valley
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Summary:We analyzed observations of microtremors and seismic ground motion to determine the depths of sedimentary interfaces and basement surface in the Kathmandu Valley. The results of these analyses and a reflection survey were combined to produce a data set of seismic depths for sedimentary interfaces and basement surface in the valley. Moreover, we introduced a data set of gravimetric depths, which had been produced for the basement surface from gravity observations. Because both sets of data differ in accuracy and number, we adopt the Sequential Gaussian Co-Simulation to generate the depth distributions of the sedimentary interfaces and basement surface. This method includes the cokriging approach, wherein the seismic and gravimetric depths are used as primary and secondary data, respectively. A three-dimensional velocity structure model of the Kathmandu Valley was constructed from the obtained depth distributions, which showed that the sedimentation in the valley is mainly related to the Paleo-Kathmandu Lake. Subsequently, we incorporated this model into a previous regional-scale model, and revised the latter to solve the issues of the extension of the underthrusting lithosphere and the S-wave velocity in its adjacent area. Graphical Abstract
ISSN:1880-5981
1343-8832
1880-5981
DOI:10.1186/s40623-023-01954-w