The 2015 Mw 8.3 Illapel, Chile, Earthquake: Direction‐Reversed Along‐Dip Rupture with Localized Water Reverberation

An, Chao; Yue, Han; Sun, Jianbao; Meng, Lingsen; Báez, J. C.

doi:10.1785/0120160393

Cited by 30 publications

(40 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…McFadden et al 1986) was used to enhance the signalto-noise ratio of the image, and the data were filtered in the 0. the kinematic BP and HBP methods. The source models of the 2015 Illapel earthquake showed a complex rupture evolution along both the up-dip and down-dip directions (Melgar et al 2016;An et al 2017;Yin et al 2018;Meng et al 2018), which is more consistent with the image obtained by the kinematic BP and HBP methods. The increased signal in the shallow part should reflect the source of high-frequency radiation from the up-dip rupture propagation.…”

Section: Application To the Real Datasupporting

confidence: 81%

Backprojection to image slip

Okuwaki¹,

Kasahara²,

Yagi³

et al. 2018

Preprint

View full text Add to dashboard Cite

SUMMARYWaveform backprojection is a key technique of earthquake-source imaging, which has been widely used for extracting information of earthquake source evolution that cannot be obtained by kinematic source inversion. The technique enjoys considerable popularity, owing to the simplicity of its implementation and the robustness of its processing, but the physical meaning of backprojection images has remained elusive. In this study, we reviewed the mathematical representation of backprojection (BP) and hybrid backprojection (HBP) methods, following the pioneering work of Fukahata et al. (Geophys. J. Int. (2014) 196, 552-559), to clarify the physical implications of BP images. We found that signal intensity in BP and HBP images is scaled with the amplitude of the Green's function that corresponds to a unit-step slip, which results in the signal intensity being depth dependent. We propose variants of BP and HBP, which we call kinematic BP and HBP, 2 R. Okuwaki, A. Kasahara, Y. Yagi, S. Hirano, and Y. Fukahata respectively, to relate the BP signal intensity to slip motion of an earthquake by modifying the normalizing factors used in the original BP and HBP methods. The original BP and HBP images remain useful for assessing the spatiotemporal strength of the wave radiation, which scales with the amplitude of the Green's function, whereas the kinematic BP and HBP methods are suitable for imaging the slip motion that is responsible for the high-frequency radiation produced during the source-rupture process.

show abstract

Section: Application To the Real Datasupporting

confidence: 81%

Backprojection to image slip

Okuwaki¹,

Kasahara²,

Yagi³

et al. 2018

Preprint

View full text Add to dashboard Cite

show abstract

“…The mainshock slip pattern and aftershock hypocenters are found to be complementary for several great earthquakes, for example, the 2010 Maule earthquake (Yue et al, ), the 2010 El Mayor‐Cucapah earthquake (S. Wei et al, ), the 2015 Gorkha earthquake (Avouac et al, ; Yue et al, ), and the 2015 Illapel earthquake (An et al, ; Melgar et al, ). Such pattern is precisely resolved for the Kumamoto earthquake.…”

Section: Resultsmentioning

confidence: 99%

The 2016 Kumamoto M_w = 7.0 Earthquake: A Significant Event in a Fault–Volcano System

et al. 2017

Self Cite

View full text Add to dashboard Cite

The 2016 Kumamoto earthquake sequence occurred on the Futagawa–Hinagu fault zone near the Aso volcano on Kyushu island. The sequence was initiated with two major (Mw ≥ 6.0) foreshocks, and the mainshock (Mw = 7.0) occurred 25 h after the second major foreshock. We combine GPS, strong motion, synthetic aperture radar images, and surface offset data in a joint inversion to resolve the kinematic rupture process of the mainshock and coseismic displacement of the foreshocks. The joint inversion results reveal a unilateral rupture process for the mainshock involving sequential rupture of four major asperities. The slip area of the foreshocks and mainshock and the aftershock loci form a detailed complementary pattern. The mainshock rupture terminates near the rim of the caldera, leaving a ~10 km long gap of aftershocks. This area is characterized by high temperature and low shear wave velocity, density, and resistivity, which may be related to the partially melted geothermal condition. Ductile material property near the volcano may act as a “material barrier” to the dynamic rupture. Topographic weight of the caldera increases compressional normal stress on the fault plane, which may behave as a “stress barrier.” Long‐term seismic hazard and deformation behaviors related to these two types of barriers are discussed in terms of the associated frictional mechanism. Significant postseismic creeps observed near the volcano area indicates a velocity strengthening frictional behavior near the rupture termination, which confirms that the “material barrier” mechanism is likely the dominant rupture termination mechanism.

show abstract

“…The subfault division has 144 patches with 12 along strike and 12 along dip, and the subfault size is 20 × 20 km. For this earthquake, the tsunami stations are mostly located along the coastal line, providing weak constraints for the rupture in the along‐dip direction (An et al, ). Therefore, we further include inland GPS and Interferometric Synthetic Aperture Radar (InSAR) data in the inversion.…”

Section: Optimum Uniform Slip Modelsmentioning

confidence: 99%

Prediction of Tsunami Waves by Uniform Slip Models

Liu

Ren

et al. 2018

JGR Oceans

Self Cite

View full text Add to dashboard Cite

Conventional tsunami warning systems for local and far‐field areas utilize uniform slip models to predict tsunami waves. The reasons are twofold. First, it is challenging to develop accurate finite‐fault slip models in a short time after an earthquake. Second, tsunami waves are long waves, and hence, the main feature may be predicted without knowing earthquake rupture details. Still, there have been few studies that quantitatively analyze the errors caused by uniform slip models. In this paper, we evaluate if and how such models may be applied for tsunami warnings. For the 2011 Tohoku, 2014 Iquique, and 2015 Illapel tsunamis, we first construct optimum uniform slip models with minimum tsunami waveform misfit and then compare the synthetic tsunami waves with finite‐fault model predictions. Predictions from both type of models match the tsunami data very well, indicating that the prediction errors caused by neglecting slip heterogeneity are insignificant. Further, we derive a common relation between the rupture area and earthquake magnitude. Additionally, the optimum rupture length and width ratio in terms of predicting tsunami waves is determined to be 1 for the three earthquakes. Lastly, we find that moving the uniform slip model to the center of global Centroid Moment Tensor solution produces reasonably small errors in the predicted waveforms. Applying the methodology to three more historic tsunamis shows that uniform slip models can well recover the Deep‐ocean Assessment and Reporting of Tsunamis system recordings, but the rupture center can differ from the global Centroid Moment Tensor solution. Our findings can potentially prompt more reliable tsunami warning strategies for future events.

show abstract

The 2015 Mw 8.3 Illapel, Chile, Earthquake: Direction‐Reversed Along‐Dip Rupture with Localized Water Reverberation

Cited by 30 publications

References 40 publications

Backprojection to image slip

Backprojection to image slip

The 2016 Kumamoto M_w = 7.0 Earthquake: A Significant Event in a Fault–Volcano System

Prediction of Tsunami Waves by Uniform Slip Models

Contact Info

Product

Resources

About

The 2015 Mw 8.3 Illapel, Chile, Earthquake: Direction‐Reversed Along‐Dip Rupture with Localized Water Reverberation

Cited by 30 publications

References 40 publications

Backprojection to image slip

Backprojection to image slip

The 2016 Kumamoto Mw = 7.0 Earthquake: A Significant Event in a Fault–Volcano System

Prediction of Tsunami Waves by Uniform Slip Models

Contact Info

Product

Resources

About

The 2016 Kumamoto M_w = 7.0 Earthquake: A Significant Event in a Fault–Volcano System