Integrating Effects of Source-Dependent Factors on Sediment-Depth Scaling of Additional Site Amplification to Ground-Motion Prediction Equation

2021 ◽  
Author(s):  
Hongwei Wang ◽  
Chunguo Li ◽  
Ruizhi Wen ◽  
Yefei Ren
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Focal Depth ◽  
Site Amplification ◽  
Prediction Equation ◽  
Sediment Depth ◽  
Long Period ◽  
Crustal Earthquakes ◽  
Additional Site ◽  
Kanto Basin

ABSTRACT It is crucial to include additional site amplification effects resulting from the thick sediment on ground motions in the reliable assessment for seismic hazard in sedimentary basins. Ground-motion residual analysis with respect to ground-motion prediction equation is performed to evaluate additional site amplifications at over 200 K-NET stations within and around Kanto basin. We first investigate the potential effects on additional site amplifications resulted from the sediment depth and several source-dependent factors. Results reveal that source-to-site distance, focal depth, and source azimuth all have nonnegligible effects on additional site amplifications, especially the focal depth. Thick sedimentary sites amplify long-period ground motions from distant earthquakes more strongly than those from local earthquakes. Ground motions from shallow crustal earthquakes generally experience much stronger amplifications than those from those deep subduction earthquakes, much more predominant for long-period ground motions (>1.0 s) at thick sedimentary sites. Meanwhile, we develop the empirical model after integrating contributions from sediment depth, source-to-site distance, and focal depth for predicting additional site amplification effects. Considering the typical case of the distant shallow crustal earthquakes, additional site amplifications at thick sedimentary sites within Kanto basin generally show an increasing trend with the oscillation period increased, whereas they are generally characterized by a decreasing trend at shallow sedimentary sites outside the basin. The mean additional site amplification is up to about 2.0 within Kanto basin, whereas 0.5–0.65 outside Kanto basin, for ground motions at oscillation periods of 2.0–5.0 s. Mean amplifications within Kanto basin are about 3.5 times larger than those outside the basin for long-period ground motions at 2.0–5.0 s. Sites northeast to Kanto basin show the largest amplifications up to about 3.0 at periods of 0.15 and 5.0 s, which may be resulted from the basin edge effects.

scholarly journals Long-Period Ground Motion Simulation Based on Three-dimensional Centroid Moment Tensor Inversion Solutions in the Kanto Region, Japan

2020 ◽  
Author(s):  
Shunsuke Takemura ◽  
Kazuo Yoshimoto ◽  
Katsuhiko Shiomi
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Moment Tensor ◽  
Three Dimensional ◽  
Centroid Moment Tensor ◽  
Velocity Models ◽  
Long Period ◽  
Ground Motion Simulations ◽  
Kanto Basin ◽  
Long Period Ground Motion

Abstract We conducted centroid moment tensor (CMT) inversions of moderate (Mw 4.5–6.5) earthquakes in the Kanto region, Japan, using a local three-dimensional (3D) model. We then investigated the effects of our 3D CMT solutions on long-period ground motion simulations. Grid search CMT inversions were conducted using displacement seismograms for periods of 25–100 s. By comparing our 3D CMT solutions with those from the local one-dimensional (1D) catalog, we found that our 3D CMT inversion systematically provides magnitudes smaller than those in the 1D catalog. The Mw differences between 3D and 1D catalogs tend to be significant for earthquakes within the oceanic slab. By comparing ground motion simulations between 1D and 3D velocity models, we confirmed that observed Mw differences could be explained by differences in the rigidity structures around the source regions between 3D and 1D velocity models. The 3D velocity structures (especially oceanic crust and mantle) are important for estimating seismic moments in intraslab earthquakes. The seismic moments directly affect the amplitudes of ground motions. Thus, 3D CMT solutions are essential for the precise forward and inverse modeling of long-period ground motion. We also conducted long-period ground motion simulations using our 3D CMT solutions to evaluate reproducibility of long-period ground motions at stations within the Kanto Basin. The simulations of our 3D CMT inversion well-reproduced observed ground motions for periods longer than 10 s, even at stations within the Kanto Basin.

scholarly journals Long-period ground motion simulation using centroid moment tensor inversion solutions based on the regional three-dimensional model in the Kanto region, Japan

2020 ◽  
Author(s):  
Shunsuke Takemura ◽  
Kazuo Yoshimoto ◽  
Katsuhiko Shiomi
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Moment Tensor ◽  
Three Dimensional ◽  
Centroid Moment Tensor ◽  
Velocity Models ◽  
Long Period ◽  
Ground Motion Simulations ◽  
Kanto Basin ◽  
Long Period Ground Motion

Abstract We conducted centroid moment tensor (CMT) inversions of moderate ( Mw 4.5–6.5) earthquakes in the Kanto region, Japan, using a local three-dimensional (3D) model. We then investigated the effects of our 3D CMT solutions on long-period ground motion simulations. Grid search CMT inversions were conducted using displacement seismograms for periods of 25–100 s. By comparing our 3D CMT solutions with those from the local one-dimensional (1D) catalog, we found that our 3D CMT inversion systematically provides magnitudes smaller than those in the 1D catalog. The Mw differences between 3D and 1D catalogs tend to be significant for earthquakes within the oceanic slab. By comparing ground motion simulations between 1D and 3D velocity models, we confirmed that observed Mw differences could be explained by differences in the rigidity structures around the source regions between 3D and 1D velocity models. The 3D velocity structures (especially oceanic crust and mantle) are important for estimating seismic moments in intraslab earthquakes, which are related to fault size estimation. A detailed discussion for intraslabe seismicity can be conducted by using the 3D CMT catalog. The seismic moments also directly affect the amplitudes of ground motions. The 3D CMT catalog allows us to directly conduct the precise forward and inverse modeling of long-period ground motion without adjusting source models, which have been typically applied in the cases using the 1D CMT catalog. We also conducted long-period ground motion simulations using our 3D CMT solutions to evaluate the reproducibility of long-period ground motions at stations within the Kanto Basin. The simulations of our 3D CMT solutions well-reproduced observed ground motions for periods longer than 10 s, even at stations within the Kanto Basin. The reproducibility of simulations was improved from those using solutions in the 1D catalog.

BC Hydro Ground Motion Prediction Equations for Subduction Earthquakes

2016 ◽  
Vol 32 (1) ◽  
pp. 23-44 ◽  
Author(s):  
Norman Abrahamson ◽  
Nicholas Gregor ◽  
Kofi Addo
Keyword(s):  
Ground Motion ◽  
Focal Depth ◽  
Site Amplification ◽  
Prediction Equation ◽  
Motion Prediction ◽  
Ground Motion Prediction ◽  
Data Set ◽  
Magnitude Scaling ◽  
Short Period ◽  
The Moment

An updated ground motion prediction equation (GMPE) for the horizontal component response spectral values from subduction zone earthquakes is developed using a global data set that includes 2,590 recordings from 63 slab earthquakes (5.0 ≤ M ≤7.9) and 953 recordings from 43 interface earthquakes (6.0 ≤ M ≤8.4) at distances up to 300 km. The empirical data constrain the moment magnitude scaling up to M8.0. For M > 8.0, a break in magnitude scaling is included in the model based on the magnitude scaling found in numerical simulations for interface earthquakes in Cascadia. The focal depth scaling of the short-period spectral values are strong for slab earthquakes, but it is not seen for interface events. The distance scaling is different for sites located in the forearc and backarc regions, with much steeper attenuation for backarc sites. The site is classified by V S30 with constrained nonlinear site amplification effects.

Ground motion and site effect observations in the wellington region from the 2016 Mw7.8 Kaikōura, New Zealand earthquake

2017 ◽  
Vol 50 (2) ◽  
pp. 94-105 ◽  
Author(s):  
Brendon A. Bradley ◽  
Liam M. Wotherspoon ◽  
Anna E. Kaiser
Keyword(s):  
Ground Motion ◽  
Site Response ◽  
Ground Motions ◽  
Site Effect ◽  
Site Amplification ◽  
Design Standards ◽  
Site Class ◽  
Near Surface ◽  
Long Period ◽  
Basin Edge

This paper presents ground motion and site effect observations in the greater Wellington region from the 14 November 2016 Mw7.8 Kaikōura earthquake. The region was the principal urban area to be affected by the earthquake-induced ground motions from this event. Despite being approximately 60km from the northern extent of the causative earthquake rupture, the ground motions in Wellington exhibited long period (specifically T = 1 - 3s) ground motion amplitudes that were similar to, and in some locations exceeded, the current 500 year return period design ground motion levels. Several ground motion observations on rock provide significant constraint to understand the role of surficial site effects in the recorded ground motions. The largest long period ground motions were observed in the Thorndon and Te Aro basins in Wellington City, inferred as a result of 1D impedance contrasts and also basin-edge-generated waves. Observed site amplifications, based on response spectral ratios with reference rock sites, are seen to significantly exceed the site class factors in NZS1170.5:2004 for site class C, D, and E sites at approximately T=0.3-3.0s. The 5-95% Significant Duration, Ds595, of ground motions was on the order of 30 seconds, consistent with empirical models for this earthquake magnitude and source-to-site distance. Such durations are slightly longer than the corresponding Ds595 = 10s and 25s in central Christchurch during the 22 February 2011 Mw6.2 and 4 September 2010 Mw7.1 earthquakes, but significantly shorter than what might be expected for large subduction zone earthquakes that pose a hazard to the region. In summary, the observations highlight the need to better understand and quantify basin and near-surface site response effects through more comprehensive models, and better account for such effects through site amplification factors in design standards.

scholarly journals Long-period ground motion simulation using centroid moment tensor inversion solutions based on the regional three-dimensional model in the Kanto region, Japan

2020 ◽  
Author(s):  
Shunsuke Takemura ◽  
Kazuo Yoshimoto ◽  
Katsuhiko Shiomi
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Moment Tensor ◽  
Three Dimensional ◽  
Centroid Moment Tensor ◽  
Velocity Models ◽  
Long Period ◽  
Ground Motion Simulations ◽  
Kanto Basin ◽  
Long Period Ground Motion

Abstract We conducted centroid moment tensor (CMT) inversions of moderate (Mw 4.5–6.5) earthquakes in the Kanto region, Japan, using a local three-dimensional (3D) model. We then investigated the effects of our 3D CMT solutions on long-period ground motion simulations. Grid search CMT inversions were conducted using displacement seismograms for periods of 25–100 s. By comparing our 3D CMT solutions with those from the local one-dimensional (1D) catalog, we found that our 3D CMT inversion systematically provides magnitudes smaller than those in the 1D catalog. The Mw differences between 3D and 1D catalogs tend to be significant for earthquakes within the oceanic slab. By comparing ground motion simulations between 1D and 3D velocity models, we confirmed that observed Mw differences could be explained by differences in the rigidity structures around the source regions between 3D and 1D velocity models. The 3D velocity structures (especially oceanic crust and mantle) are important for estimating seismic moments in intraslab earthquakes, which are related to fault size estimation. A detailed discussion for intraslabe seismicity can be conducted by using the 3D CMT catalog. The seismic moments also directly affect the amplitudes of ground motions. The 3D CMT catalog allows us to directly conduct the precise forward and inverse modeling of long-period ground motion without adjusting source models, which have been typically applied in the cases using the 1D CMT catalog. We also conducted long-period ground motion simulations using our 3D CMT solutions to evaluate the reproducibility of long-period ground motions at stations within the Kanto Basin. The simulations of our 3D CMT solutions well-reproduced observed ground motions for periods longer than 10 s, even at stations within the Kanto Basin. The reproducibility of simulations was improved from those using solutions in the 1D catalog.

NGA-West2 Database

2014 ◽  
Vol 30 (3) ◽  
pp. 989-1005 ◽  
Author(s):  
Timothy D. Ancheta ◽  
Robert B. Darragh ◽  
Jonathan P. Stewart ◽  
Emel Seyhan ◽  
Walter J. Silva ◽  
...  
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Prediction Equation ◽  
Ground Motion Prediction ◽  
Motion Data ◽  
Crustal Earthquakes ◽  
Active Tectonic ◽  
Quality Checks ◽  
Working Groups ◽  
Moderate Magnitude

The NGA-West2 project database expands on its predecessor to include worldwide ground motion data recorded from shallow crustal earthquakes in active tectonic regimes post-2000 and a set of small-to-moderate-magnitude earthquakes in California between 1998 and 2011. The database includes 21,336 (mostly) three-component records from 599 events. The parameter space covered by the database is M 3.0 to M 7.9, closest distance of 0.05 to 1,533 km, and site time-averaged shear-wave velocity in the top 30 m of V S30 = 94 m/s to 2,100 m/s (although data becomes sparse for distances >400 km and V S30 > 1,200 m/s or <150 m/s). The database includes uniformly processed time series and response spectral ordinates for 111 periods ranging from 0.01 s to 20 s at 11 damping ratios. Ground motions and metadata for source, path, and site conditions were subject to quality checks by ground motion prediction equation developers and topical working groups.

scholarly journals Long-period ground motion simulation using centroid moment tensor inversion solutions based on the regional three-dimensional model in the Kanto region, Japan

2020 ◽  
Author(s):  
Shunsuke Takemura ◽  
Kazuo Yoshimoto ◽  
Katsuhiko Shiomi
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Moment Tensor ◽  
Three Dimensional ◽  
Centroid Moment Tensor ◽  
Long Period ◽  
Ground Motion Simulations ◽  
Kanto Basin ◽  
Long Period Ground Motion ◽  
Kanto Region

Abstract We conducted centroid moment tensor (CMT) inversions of moderate (Mw 4.5–6.5) earthquakes in the Kanto region, Japan, using a local three-dimensional (3D) model. We then investigated the effects of our 3D CMT solutions on long-period ground motion simulations. Grid search CMT inversions were conducted using displacement seismograms for the periods of 25–100 s. By comparing our 3D CMT solutions with those from the local one-dimensional (1D) catalog, we found that our 3D CMT inversion systematically provides magnitudes smaller than those in the 1D catalog. The Mw differences between 3D and 1D catalogs tend to be significant for earthquakes within the oceanic slab. By comparing the ground motion simulations of the 1D and 3D velocity models, we confirmed that the observed Mw differences could be explained by the differences in the rigidity structures around the source regions in the two models. The 3D velocity structures (especially oceanic crust and mantle) are important for estimating seismic moments in intraslab earthquakes. The seismic moments directly affect the amplitudes of ground motions. Thus, 3D CMT solutions are essential for precise forward and inverse modeling of long-period ground motion. We also conducted long-period ground motion simulations using our 3D CMT solutions to evaluate the reproducibility of long-period ground motions at stations within the Kanto Basin. The simulations of our 3D CMT solutions well-reproduced observed ground motions for periods longer than 10 s, even at stations within the Kanto Basin. The reproducibility of simulations using our 3D CMT solutions was better than those based on the solutions in the 1D catalog.

An NGA Model for the Average Horizontal Component of Peak Ground Motion and Response Spectra

2008 ◽  
Vol 24 (1) ◽  
pp. 173-215 ◽  
Author(s):  
BrianS-J. Chiou ◽  
Robert R. Youngs
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Hanging Wall ◽  
Response Spectra ◽  
Horizontal Component ◽  
Smooth Functions ◽  
Soil Response ◽  
New Model ◽  
Crustal Earthquakes ◽  
Aleatory Variability

We present a model for estimating horizontal ground motion amplitudes caused by shallow crustal earthquakes occurring in active tectonic environments. The model provides predictive relationships for the orientation-independent average horizontal component of ground motions. Relationships are provided for peak acceleration, peak velocity, and 5-percent damped pseudo-spectral acceleration for spectral periods of 0.01 to 10 seconds. The model represents an update of the relationships developed by Sadigh et. al. (1997) and incorporates improved magnitude and distance scaling forms as well as hanging-wall effects. Site effects are represented by smooth functions of average shear wave velocity of the upper 30 m ( VS30) and sediment depth. The new model predicts median ground motion that is similar to Sadigh et. al. (1997) at short spectral period, but lower ground motions at longer periods. The new model produces slightly lower ground motions in the distance range of 10 to 50 km and larger ground motions at larger distances. The aleatory variability in ground motion amplitude was found to depend upon earthquake magnitude and on the degree of nonlinear soil response, For large magnitude earthquakes, the aleatory variability is larger than found by Sadigh et. al. (1997).

Testing non-linear amplification factors used in ground motion models

2021 ◽  
Author(s):  
Karina Loviknes ◽  
Danijel Schorlemmer ◽  
Fabrice Cotton ◽  
Sreeram Reddy Kotha
Keyword(s):  
Ground Motion ◽  
Site Effects ◽  
Ground Motions ◽  
Site Amplification ◽  
Building Codes ◽  
Linear Amplification ◽  
Motion Models ◽  
Earthquake Predictability ◽  
Non Linear ◽  
Ground Motion Models

&lt;p&gt;Non-linear site effects are mainly expected for strong ground motions and sites with soft soils and more recent ground-motion models (GMM) have started to include such effects. Observations in this range are, however, sparse, and most non-linear site amplification models are therefore partly or fully based on numerical simulations. We develop a framework for testing of non-linear site amplification models using data from the comprehensive Kiban-Kyoshin network in Japan. The test is reproducible, following the vision of the Collaboratory for the Study of Earthquake Predictability (CSEP), and takes advantage of new large datasets to evaluate &lt;span&gt;whether or not&lt;/span&gt; non-linear site effects predicted by site-amplification models are supported by empirical data. The site amplification models are tested using residuals between the observations and predictions from a GMM based only on magnitude and distance. When the GMM is derived without any site term, the site-specific variability extracted from the residuals is expected to capture the site response of a site. The non-linear site amplification models are tested against a linear amplification model on individual well-record&lt;span&gt;ing&lt;/span&gt; stations. Finally, the result is compared to building codes where non-linearity is included. The test shows that for most of the sites selected as having sufficient records, the non-linear site-amplification models do not score better than the linear amplification model. This suggests that including non-linear site amplification in GMMs and building codes may not yet be justified, at least not in the range of ground motions considered in the test (peak ground acceleration &lt; 0.2 g).&lt;/p&gt;

Optimizing Earthquake Early Warning Alert Distance Strategies Using the July 2019 Mw 6.4 and Mw 7.1 Ridgecrest, California, Earthquakes

2020 ◽  
Vol 110 (4) ◽  
pp. 1872-1886 ◽  
Author(s):  
Jessie K. Saunders ◽  
Brad T. Aagaard ◽  
Annemarie S. Baltay ◽  
Sarah E. Minson
Keyword(s):  
Ground Motion ◽  
Early Warning ◽  
Ground Motions ◽  
Protective Action ◽  
Warning System ◽  
Prediction Equation ◽  
Earthquake Early Warning ◽  
Source Characterization ◽  
Earthquake Early Warning System ◽  
Alert Distance

ABSTRACT The ShakeAlert earthquake early warning system aims to alert people who experience modified Mercalli intensity (MMI) IV+ shaking during an earthquake using source estimates (magnitude and location) to estimate median-expected peak ground motions with distance, then using these ground motions to determine median-expected MMI and thus the extent of MMI IV shaking. Because median ground motions are used, even if magnitude and location are correct, there will be people outside the alert region who experience MMI IV shaking but do not receive an alert (missed alerts). We use 91,000 “Did You Feel It?” survey responses to the July 2019 Mw 6.4 and Mw 7.1 Ridgecrest, California, earthquakes to determine which ground-motion to intensity conversion equation (GMICE) best fits median MMI with distance. We then explore how incorporating uncertainty from the ground-motion prediction equation and the GMICE in the alert distance calculation can produce more accurate MMI IV alert regions for a desired alerting strategy (e.g., aiming to alert 95% of people who experience MMI IV+ shaking), assuming accurate source characterization. Without incorporating ground-motion uncertainties, we find MMI IV alert regions using median-expected ground motions alert fewer than 20% of the population that experiences MMI IV+ shaking. In contrast, we find &gt;94% of the people who experience MMI IV+ shaking can be included in the MMI IV alert region when two standard deviations of ground-motion uncertainty are included in the alert distance computation. The optimal alerting strategy depends on the false alert tolerance of the community due to the trade-off between minimizing missed and false alerts. This is especially the case for situations like the Mw 6.4 earthquake when alerting 95% of the 5 million people who experience MMI IV+ also results in alerting 14 million people who experience shaking below this level and do not need to take protective action.

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