Considering rupture directivity effects, which structures should be named ‘long-period buildings’?

2010 ◽  
Vol 22 (2) ◽  
pp. 165-178 ◽  
Author(s):  
S. Farid Ghahari ◽  
A. Reza Khaloo
Keyword(s):  
Rupture Directivity ◽  
Long Period ◽  
Directivity Effects

Strong‐Motion Directionality and Evidence of Rupture Directivity Effects during the Chi‐Chi Mw 7.6 Earthquake

2019 ◽  
Vol 109 (6) ◽  
pp. 2367-2383
Author(s):  
Junju Xie
Keyword(s):  
Strong Motion ◽  
Clear Correlation ◽  
Rupture Directivity ◽  
Intensity Measures ◽  
Long Period ◽  
Forward Directivity ◽  
Chelungpu Fault ◽  
Fling Step ◽  
Motion Directionality ◽  
Directivity Effects

Abstract This article investigates the spatial distribution, predominant direction, and variations in the intensity measures (IMs) with orientation for classified pulse‐like and nonpulse motions during Chi‐Chi Mw 7.6 earthquake. The results show evidence of high polarization for long‐period spectral accelerations at relatively large source‐to‐site distances (50–100 km) north of the Chelungpu fault. The polarization of long‐period motions shows a clear correlation with the directivity parameters’ isochrone directivity predictor and ξ, indicating a connection between directionality and rupture directivity. The variation in strong‐motion directionality with the period is also studied. The discrepancy in directionality caused by strong directivity increases with the period from 1 to 10 s, which confirms a clear correlation of period‐dependent directionality with directivity effects. This study finds stronger directionality of pulse‐like motions than nonpulse motions for long periods over 3 s with higher maximum‐to‐median and maximum‐to‐minimum IM ratios. For periods over 3 s, the maximum‐to‐median ratios of pulse‐like motions are higher than the mean prediction of the Shahi and Baker (2014a) model, whereas those of nonpulse motions are lower than the prediction. However, this study does not find simple and clear results for the directions of the maximum component at different periods for pulse‐like and nonpulse motions. Despite clear differences between the unidirectional fling‐step and bidirectional forward directivity pulses, the effects of fling‐step and forward directivity are actually coupled in the waveforms.

scholarly journals Rupture Directivity in 3D Inferred From Acoustic Emissions Events in a Mine-Scale Hydraulic Fracturing Experiment

2021 ◽  
Vol 9 ◽  
Author(s):  
José Ángel López-Comino ◽  
Simone Cesca ◽  
Peter Niemz ◽  
Torsten Dahm ◽  
Arno Zang
Keyword(s):  
Hydraulic Fracturing ◽  
Acoustic Emissions ◽  
Local Stress ◽  
Horizontal Stress ◽  
Monitoring Networks ◽  
Rupture Directivity ◽  
Shallow Subsurface ◽  
Minimum Horizontal Stress ◽  
Directivity Effects ◽  
Full Waveforms

Rupture directivity, implying a predominant earthquake rupture propagation direction, is typically inferred upon the identification of 2D azimuthal patterns of seismic observations for weak to large earthquakes using surface-monitoring networks. However, the recent increase of 3D monitoring networks deployed in the shallow subsurface and underground laboratories toward the monitoring of microseismicity allows to extend the directivity analysis to 3D modeling, beyond the usual range of magnitudes. The high-quality full waveforms recorded for the largest, decimeter-scale acoustic emission (AE) events during a meter-scale hydraulic fracturing experiment in granites at ∼410 m depth allow us to resolve the apparent durations observed at each AE sensor to analyze 3D-directivity effects. Unilateral and (asymmetric) bilateral ruptures are then characterized by the introduction of a parameter κ, representing the angle between the directivity vector and the station vector. While the cloud of AE activity indicates the planes of the hydrofractures, the resolved directivity vectors show off-plane orientations, indicating that rupture planes of microfractures on a scale of centimeters have different geometries. Our results reveal a general alignment of the rupture directivity with the orientation of the minimum horizontal stress, implying that not only the slip direction but also the fracture growth produced by the fluid injections is controlled by the local stress conditions.

Comparison of Ground Motions from Hybrid Simulations to NGA Prediction Equations

2011 ◽  
Vol 27 (2) ◽  
pp. 331-350 ◽  
Author(s):  
Lisa M. Star ◽  
Jonathan P. Stewart ◽  
Robert W. Graves
Keyword(s):  
Ground Motions ◽  
Rupture Directivity ◽  
Ground Motion Prediction Equations ◽  
Fault Rupture ◽  
Prediction Equations ◽  
San Andreas ◽  
Blind Thrust ◽  
Static Stress Drop ◽  
Basin Response ◽  
Directivity Effects

We compare simulated motions for a Mw 7.8 rupture scenario on the San Andreas Fault known as the ShakeOut event, two permutations with different hypocenter locations, and a Mw 7.15 Puente Hills blind thrust scenario, to median and dispersion predictions from empirical NGA ground motion prediction equations. We find the simulated motions attenuate faster with distance than is predicted by the NGA models for periods less than about 5.0 s After removing this distance attenuation bias, the average residuals of the simulated events (i.e., event terms) are generally within the scatter of empirical event terms, although the ShakeOut simulation appears to be a high static stress drop event. The intra-event dispersion in the simulations is lower than NGA values at short periods and abruptly increases at 1.0 s due to different simulation procedures at short and long periods. The simulated motions have a depth-dependent basin response similar to the NGA models, and also show complex effects in which stronger basin response occurs when the fault rupture transmits energy into a basin at low angle, which is not predicted by the NGA models. Rupture directivity effects are found to scale with the isochrone parameter.

Rupture Directivity Effects on Strong Ground Motion during the 15 April 2016Mw 7.0 Kumamoto Earthquake in Japan

2017 ◽  
Vol 107 (3) ◽  
pp. 1265-1276 ◽  
Author(s):  
Junju Xie ◽  
Paolo Zimmaro ◽  
Xiaojun Li ◽  
Zengping Wen
Keyword(s):  
Ground Motion ◽  
Strong Ground Motion ◽  
Rupture Directivity ◽  
Kumamoto Earthquake ◽  
Directivity Effects ◽  
Strong Ground

scholarly journals Seismic hazard assessment of Tehran, Iran with emphasis on near-fault rupture directivity effects

2018 ◽  
Vol 31 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Ehsan Bazarchi ◽  
◽  
Reza Saberi ◽  
Majid Alinejad ◽  
◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Hazard Assessment ◽  
Seismic Hazard Assessment ◽  
Rupture Directivity ◽  
Fault Rupture ◽  
Near Fault ◽  
Directivity Effects

The 4th February 1997 Bojnurd (Garmkhan) Earthquake in NE Iran: Field, Teleseismic, and Strong-Motion Evidence for Rupture Directivity Effects on a Strike-Slip Fault

2007 ◽  
Vol 11 (2) ◽  
pp. 193-214 ◽  
Author(s):  
James Hollingsworth ◽  
James Jackson ◽  
John E. Alarcón ◽  
Julian J. Bommer ◽  
Mohammad Javad Bolourchi
Keyword(s):  
Strong Motion ◽  
Strike Slip ◽  
Strike Slip Fault ◽  
Rupture Directivity ◽  
Directivity Effects ◽  
Ne Iran

scholarly journals Prevalence of asymmetrical rupture in small earthquakes and its effect on the estimation of stress drop: a systematic investigation in inland Japan

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Keisuke Yoshida
Keyword(s):  
Seismic Waves ◽  
Source Parameters ◽  
Systematic Investigation ◽  
Rupture Propagation ◽  
Rupture Directivity ◽  
Earthquake Sources ◽  
Rate Functions ◽  
Rupture Model ◽  
Stress Drops ◽  
Directivity Effects

AbstractStress drops of small earthquakes have been estimated under the assumption that the rupture propagates symmetrically within a circular fault. However, recent studies have observed directivity effects on seismic waves even for small earthquakes. In this study, rupture directivity was investigated systematically for small-to-moderate-sized earthquakes (M 3.5–5.5) that occurred beneath inland Japan from 2004 to April 2019. Apparent moment rate functions were determined for 1463 earthquakes, and their corner frequencies were inverted for their rupture parameters. The results indicate that most of the analyzed earthquakes (1217 of 1463) are characterized by significantly asymmetrical rupture propagation. The stress drops of the earthquakes estimated by considering asymmetrical rupture propagation were 16.8 MPa, which are almost twice the estimates based on the commonly used symmetrical rupture model. This shows the importance of recognizing the diversity of ruptures, even for small earthquakes, for extracting information about earthquake sources and the Earth’s structure. The prevailing rupture directivity can provide useful information on source parameters including the fault size, fault geometry, and rupture velocity of small earthquakes.

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