scholarly journals Study on the Nonlinear Site Response Using the Green's Functions of a Near-Surface Layer Estimated for Weak Motions-Borehole Array Recordings at the IWTH25 Site for the 2008 Iwate-Miyagi Inland Earthquake (M7.2)-

2011 ◽  
Vol 63 (4) ◽  
pp. 197-206
Author(s):  
Yukari TANAKA ◽  
Shigeo KINOSHITA
Keyword(s):  
Surface Layer ◽  
Green's Functions ◽  
Green’S Functions ◽  
Site Response ◽  
Near Surface ◽  
Nonlinear Site Response ◽  
Inland Earthquake ◽  
Array Recordings

scholarly journals Developing a model for the prediction of ground motions due to earthquakes in the Groningen gas field

2017 ◽  
Vol 96 (5) ◽  
pp. s203-s213 ◽  
Author(s):  
Julian J. Bommer ◽  
Bernard Dost ◽  
Benjamin Edwards ◽  
Pauline P. Kruiver ◽  
Michail Ntinalexis ◽  
...  
Keyword(s):  
Ground Motion ◽  
Site Response ◽  
Ground Motions ◽  
Essential Element ◽  
Mitigation Measures ◽  
Gas Field ◽  
Near Surface ◽  
Nonlinear Site Response ◽  
Wide Range ◽  
Groningen Gas Field

AbstractMajor efforts are being undertaken to quantify seismic hazard and risk due to production-induced earthquakes in the Groningen gas field as the basis for rational decision-making about mitigation measures. An essential element is a model to estimate surface ground motions expected at any location for each earthquake originating within the gas reservoir. Taking advantage of the excellent geological and geophysical characterisation of the field and a growing database of ground-motion recordings, models have been developed for predicting response spectral accelerations, peak ground velocity and ground-motion durations for a wide range of magnitudes. The models reflect the unique source and travel path characteristics of the Groningen earthquakes, and account for the inevitable uncertainty in extrapolating from the small observed magnitudes to potential larger events. The predictions of ground-motion amplitudes include the effects of nonlinear site response of the relatively soft near-surface deposits throughout the field.

scholarly journals Validation of a fast semi-analytic method for surface-wave propagation in layered media

2019 ◽  
Vol 219 (2) ◽  
pp. 1405-1420 ◽  
Author(s):  
Quentin Brissaud ◽  
Victor C Tsai
Keyword(s):  
Wave Propagation ◽  
Surface Wave ◽  
Power Law ◽  
Green's Functions ◽  
Green’S Functions ◽  
Shear Velocity ◽  
Surface Velocity ◽  
Near Surface ◽  
Phase Velocities ◽  
Surface Wave Propagation

SUMMARY Green’s functions provide an efficient way to model surface-wave propagation and estimate physical quantities for near-surface processes. Several surface-wave Green’s function approximations (far-field, no mode conversions and no higher mode surface waves) have been employed for numerous applications such as estimating sediment flux in rivers, determining the properties of landslides, identifying the seismic signature of debris flows or to study seismic noise through cross-correlations. Based on those approximations, simple empirical scalings exist to derive phase velocities and amplitudes for pure power-law velocity structures providing an exact relationship between the velocity model and the Green’s functions. However, no quantitative estimates of the accuracy of these simple scalings have been reported for impulsive sources in complex velocity structures. In this paper, we address this gap by comparing the theoretical predictions to high-order numerical solutions for the vertical component of the wavefield. The Green’s functions computation shows that attenuation-induced dispersion of phase and group velocity plays an important role and should be carefully taken into account to correctly describe how surface-wave amplitudes decay with distance. The comparisons confirm the general reliability of the semi-analytic model for power-law and realistic shear velocity structures to describe fundamental-mode Rayleigh waves in terms of characteristic frequencies, amplitudes and envelopes. At short distances from the source, and for large near-surface velocity gradients or high Q values, the low-frequency energy can be dominated by higher mode surface waves that can be captured by introducing additional higher mode Rayleigh-wave power-law scalings. We also find that the energy spectral density for realistic shear-velocity models close to piecewise power-law models can be accurately modelled using the same non-dimensional scalings. The frequency range of validity of each power-law scaling can be derived from the corresponding phase velocities. Finally, highly discontinuous near-surface velocity profiles can also be approximated by a combination of power-law scalings. Analytical Green’s functions derived from the non-dimensionalization provide a good estimate of the amplitude and variations of the energy distribution, although the predictions are quite poor around the frequency bounds of each power-law scaling.

Impact of Geometric Effects on Near-Surface Green's Functions

2013 ◽  
Vol 103 (6) ◽  
pp. 3289-3304 ◽  
Author(s):  
F. De Martin ◽  
S. Matsushima ◽  
H. Kawase
Keyword(s):  
Green's Functions ◽  
Green’S Functions ◽  
Near Surface ◽  
Geometric Effects

An Improved Method for Computing Broadband Green’s Functions of Surface Sources and Its Application to Inverting the Processes of the 2017 Xinmo Landslide

2021 ◽  
Author(s):  
Yunyi Qian ◽  
Zhengbo Li ◽  
Xiaofei Chen
Keyword(s):  
Green's Functions ◽  
Green’S Functions ◽  
Complex Surface ◽  
Dominant Frequency ◽  
Improved Method ◽  
Transmission Method ◽  
Surface Source ◽  
Near Surface ◽  
Xinmo Landslide ◽  
Initiation Stage

Abstract Landslides are dramatic and complex surface processes that can result in extensive casualties and property damage. The broadband seismic signals generated by landslides provide datasets essential for understanding time-dependent sliding processes. However, traditional methods for computing Green’s functions based on wavenumber integration converge very slowly for surface sources, especially at high frequencies. Usually, long-period synthetic waves with a cutoff k-integral for an approximated near-surface source are adopted for landslide studies, which may lead to artifacts. Thus, the development of efficient methods for computing the broadband Green’s functions of surface sources is important. The generalized reflection and transmission method with the peak-trough averaging technique can overcome the difficulties in wavenumber integration for surface sources, quickly converging even for high-frequency calculations. We use this improved method to compute Green’s functions for surface single-force sources and invert the force histories of the 2017 devastating Xinmo landslide in different frequency bands. The results indicate that the complex sliding process of this drastic event can be revealed by broadband signals (0.02–0.5 Hz), and that the initiation stage of this event shows a dominant frequency up to 0.2 Hz.

Magnitude of nonlinear sediment response in Los Angeles basin during the 1994 Northridge, California, earthquake

1998 ◽  
Vol 88 (4) ◽  
pp. 1079-1084
Author(s):  
Igor A. Beresnev ◽  
Edward H. Field ◽  
Koen Van Den Abeele ◽  
Paul A. Johnson
Keyword(s):  
Los Angeles ◽  
Site Response ◽  
Accurate Estimation ◽  
Frequency Change ◽  
Los Angeles Basin ◽  
Near Surface ◽  
Nonlinear Site Response ◽  
Lower Amplitude ◽  
Modulus Reduction ◽  
Entire Ensemble

Abstract The study of nonlinear site response has practical difficulties due to large ambiguities in isolating local response from other competing effects. We chose a sedimentary site LF6 in Los Angeles basin that (1) has the closest reference rock sites available, compared to other stations, allowing an accurate estimation of local amplification, and (2) illustrates clear resonance in the near surface. In our opinion, this case represents the least ambiguity in the identification of possible nonlinearity. The site responses during the Northridge, the 1987 Whittier Narrows events and the Northridge aftershocks are compared. The station shows a fundamental resonance-frequency change between the higher- and lower-amplitude motions in the entire ensemble of 17 events used. The net shear-modulus reduction during the Northridge event is a factor of 1.3 to 1.4 compared to the Whittier Narrows event and is a factor of 1.7 compared to the aftershocks. This result provides guidance of what to expect at other sites in the basin, where the nonlinear response is less easy to characterize.

Recombination Characteristics of Single-Crystalline Silicon Wafers with a Damaged Near-Surface Layer

2013 ◽  
Vol 58 (2) ◽  
pp. 142-150 ◽  
Author(s):  
A.V. Sachenko ◽  
◽  
V.P. Kostylev ◽  
V.G. Litovchenko ◽  
V.G. Popov ◽  
...  
Keyword(s):  
Surface Layer ◽  
Crystalline Silicon ◽  
Silicon Wafers ◽  
Single Crystalline Silicon ◽  
Near Surface ◽  
Single Crystalline
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