scholarly journals Benchmarking the Optimal Time Alignment of Tsunami Waveforms in Nonlinear Joint Inversions for the Mw 8.8 2010 Maule (Chile) Earthquake

2020 ◽  
Vol 8 ◽  
Author(s):  
F. Romano ◽  
S. Lorito ◽  
T. Lay ◽  
A. Piatanesi ◽  
M. Volpe ◽  
...  
Keyword(s):  
Coseismic Deformation ◽  
Optimal Time ◽  
Tide Gauges ◽  
First Order ◽  
Time Alignment ◽  
Finite Fault ◽  
Chile Earthquake ◽  
Tsunami Waveforms ◽  
Maule Earthquake ◽  
Seafloor Deformation

Finite-fault models for the 2010 Mw 8.8 Maule, Chile earthquake indicate bilateral rupture with large-slip patches located north and south of the epicenter. Previous studies also show that this event features significant slip in the shallow part of the megathrust, which is revealed through correction of the forward tsunami modeling scheme used in tsunami inversions. The presence of shallow slip is consistent with the coseismic seafloor deformation measured off the Maule region adjacent to the trench and confirms that tsunami observations are particularly important for constraining far-offshore slip. Here, we benchmark the method of Optimal Time Alignment (OTA) of the tsunami waveforms in the joint inversion of tsunami (DART and tide-gauges) and geodetic (GPS, InSAR, land-leveling) observations for this event. We test the application of OTA to the tsunami Green’s functions used in a previous inversion. Through a suite of synthetic tests we show that if the bias in the forward model is comprised only of delays in the tsunami signals, the OTA can correct them precisely, independently of the sensors (DART or coastal tide-gauges) and, to the first-order, of the bathymetric model used. The same suite of experiments is repeated for the real case of the 2010 Maule earthquake where, despite the results of the synthetic tests, DARTs are shown to outperform tide-gauges. This gives an indication of the relative weights to be assigned when jointly inverting the two types of data. Moreover, we show that using OTA is preferable to subjectively correcting possible time mismatch of the tsunami waveforms. The results for the source model of the Maule earthquake show that using just the first-order modeling correction introduced by OTA confirms the bilateral rupture pattern around the epicenter, and, most importantly, shifts the inferred northern patch of slip to a shallower position consistent with the slip models obtained by applying more complex physics-based corrections to the tsunami waveforms. This is confirmed by a slip model refined by inverting geodetic and tsunami data complemented with a denser distribution of GPS data nearby the source area. The models obtained with the OTA method are finally benchmarked against the observed seafloor deformation off the Maule region. We find that all of the models using the OTA well predict this offshore coseismic deformation, thus overall, this benchmarking of the OTA method can be considered successful.

Optimal time alignment of tide-gauge tsunami waveforms in nonlinear inversions: Application to the 2015 Illapel (Chile) earthquake

2016 ◽  
Vol 43 (21) ◽  
pp. 11,226-11,235 ◽  
Author(s):  
F. Romano ◽  
A. Piatanesi ◽  
S. Lorito ◽  
C. Tolomei ◽  
S. Atzori ◽  
...  
Keyword(s):  
Tide Gauge ◽  
Optimal Time ◽  
Time Alignment ◽  
Chile Earthquake ◽  
Tsunami Waveforms

scholarly journals Co-Seismic and Post-Seismic Temporal and Spatial Gravity Changes of the 2010 Mw 8.8 Maule Chile Earthquake Observed by GRACE and GRACE Follow-on

2020 ◽  
Vol 12 (17) ◽  
pp. 2768
Author(s):  
Wei Qu ◽  
Yaxi Han ◽  
Zhong Lu ◽  
Dongdong An ◽  
Qin Zhang ◽  
...  
Keyword(s):  
Gravitational Field ◽  
Hanging Wall ◽  
Suppressive Effect ◽  
Gravity Gradient ◽  
Dislocation Model ◽  
Seismogenic Fault ◽  
First Order ◽  
Gravity Changes ◽  
Maule Earthquake ◽  
Temporal And Spatial

The Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow-on (GRACE-FO) satellites are important for studying regional gravitational field changes caused by strong earthquakes. In this study, we chose Chile, one of Earth’s most active seismic zones to explore the co-seismic and post-seismic gravitational field changes of the 2010 Mw 8.8 Maule earthquake based on longer-term GRACE and the newest GRACE-FO data. We calculated the first-order co-seismic gravity gradient changes (GGCs) and probed the geodynamic characteristics of the earthquake. The earthquake caused significant positive gravity change on the footwall and negative gravity changes on the hanging wall of the seismogenic fault. The time series of gravity changes at typical points all clearly revealed an abrupt change caused by the earthquake. The first-order northern co-seismic GGCs had a strong suppressive effect on the north-south strip error. GRACE-FO results showed that the latest post-seismic gravity changes had obvious inherited development characteristics, and that the west coast of Chile maybe still affected by the post-seismic effect. The cumulative gravity changes simulated based on viscoelastic dislocation model is approximately consistent with the longer-term GRACE and the newest GRACE-FO observations. Our results provide important reference for understanding temporal and spatial gravity variations associated with the co-seismic and post-seismic processes of the 2010 Maule earthquake.

Performance of Port Facilities in Southern Chile during the 27 February 2010 Maule Earthquake

2012 ◽  
Vol 28 (1_suppl1) ◽  
pp. 553-579 ◽  
Author(s):  
Santiago Brunet ◽  
Juan Carlos de la Llera ◽  
Andrés Jacobsen ◽  
Eduardo Miranda ◽  
Cristián Meza
Keyword(s):  
Lateral Spreading ◽  
Soil Liquefaction ◽  
Southern Chile ◽  
Port Facilities ◽  
Chile Earthquake ◽  
Design Values ◽  
Maule Earthquake ◽  
Structural Failures ◽  
2010 Maule Earthquake ◽  
Nonlinear Deformations

This article describes the seismic performance of a group of ports in southern Chile during the 27 February 2010 Maule, Chile, earthquake. Direct costs in damage for these ports have been estimated in slightly less than US$300 million. Similarly to the performance of other ports in previous earthquakes, the most common failures observed were soil related, and include soil liquefaction, lateral spreading, and pile failures. Structural failures were mostly due to short pile effects and natural torsion. This situation is contrasted herein with the performance of the South Coronel Pier, which was seismically isolated in 2007. The isolated portion of this port remained operational after the earthquake, which was the main design goal. Post-earthquake preliminary analyses indicate that the structure was subjected to deformations and forces of approximately 60% to 70% of their design values, respectively. Piles and superstructure remained within elastic range, while the isolators experienced important nonlinear deformations.

scholarly journals Fault slip distribution of the 2014 Iquique, Chile, earthquake estimated from ocean-wide tsunami waveforms and GPS data

2015 ◽  
Vol 42 (4) ◽  
pp. 1053-1060 ◽  
Author(s):  
Aditya Riadi Gusman ◽  
Satoko Murotani ◽  
Kenji Satake ◽  
Mohammad Heidarzadeh ◽  
Endra Gunawan ◽  
...  
Keyword(s):  
Fault Slip ◽  
Slip Distribution ◽  
Gps Data ◽  
Chile Earthquake ◽  
Tsunami Waveforms ◽  
Fault Slip Distribution

scholarly journals The Collapse of the Alto Río Building during the 27 February 2010 Maule, Chile, Earthquake

2012 ◽  
Vol 28 (1_suppl1) ◽  
pp. 301-334 ◽  
Author(s):  
Cheng Song ◽  
Santiago Pujol ◽  
Andrés Lepage
Keyword(s):  
Reinforced Concrete ◽  
Building Code ◽  
Field Observations ◽  
Structural Walls ◽  
Floor Area ◽  
Chile Earthquake ◽  
Maule Earthquake ◽  
2010 Maule Earthquake ◽  
Story Building

The Alto Río Building, a 15-story building located in Concepción, Chile, collapsed during the 2010 Maule earthquake. Construction of the building was completed in 2009 following the Chilean building code of 1996. The building was provided with reinforced concrete structural walls (occupying nearly 7% of the floor area) to resist lateral and vertical loads. The walls failed in the first story, causing the overturning of the entire building. This paper provides detailed field observations and discusses plausible causes of the collapse.

scholarly journals Multi-scale Modelling of Segmentation

2016 ◽  
Vol 34 (2) ◽  
pp. 192-217 ◽  
Author(s):  
Martín Hartmann ◽  
Olivier Lartillot ◽  
Petri Toiviainen
Keyword(s):  
Real Time ◽  
Time Scales ◽  
Time Lag ◽  
Optimal Time ◽  
Boundary Density ◽  
Multi Scale ◽  
Time Alignment ◽  
Scale Modelling ◽  
Time Segmentation ◽  
Segmentation Models

While listening to music, people often unwittingly break down musical pieces into constituent chunks such as verses and choruses. Music segmentation studies have suggested that some consensus regarding boundary perception exists, despite individual differences. However, neither the effects of experimental task (i.e., real-time vs. annotated segmentation), nor of musicianship on boundary perception are clear. Our study assesses musicianship effects and differences between segmentation tasks. We conducted a real-time experiment to collect segmentations by musicians and nonmusicians from nine musical pieces. In a second experiment on non-real-time segmentation, musicians indicated boundaries and their strength for six examples. Kernel density estimation was used to develop multi-scale segmentation models. Contrary to previous research, no relationship was found between boundary strength and boundary indication density, although this might be contingent on stimuli and other factors. In line with other studies, no musicianship effects were found: our results showed high agreement between groups and similar inter-subject correlations. Also consistent with previous work, time scales between one and two seconds were optimal for combining boundary indications. In addition, we found effects of task on number of indications, and a time lag between tasks dependent on beat length. Also, the optimal time scale for combining responses increased when the pulse clarity or event density decreased. Implications for future segmentation studies are raised concerning the selection of time scales for modelling boundary density, and time alignment between models.

scholarly journals Inversion of the Slip Distribution of the 2017 Ms7.0 Jiuzhaigou Earthquake From InSAR

2020 ◽  
Author(s):  
Xiongwei Tang ◽  
Rumeng Guo ◽  
Jianqiao Xu ◽  
Heping Sun ◽  
Xiaodong Chen ◽  
...  
Keyword(s):  
Tectonic Stress ◽  
Fault Model ◽  
Slip Distribution ◽  
Obtuse Angle ◽  
Coseismic Deformation ◽  
Jiuzhaigou Earthquake ◽  
The North ◽  
Finite Fault ◽  
Main Fault ◽  
Secondary Fault

Abstract On 8 August 2017, an Ms 7.0 earthquake occurred on a buried fault extending to the north of the Huya fault. Based on the coseismic deformation field obtained from Interferometric Synthetic Aperture Radar (InSAR) data and a series of finite fault model tests, we proposed a brand new two-fault model composed of a main fault and a secondary fault as the optimal model for the Jiuzhaigou earthquake, in which the secondary fault is at a large obtuse angle to the northern end of the main fault plane. Results show that the slip distribution is dominated by sinistral slip, with a significant shallow slip deficit. The main fault consists of two asperities, which is bounded by an aftershock gap may representing a barrier. In addition, we find that most of the aftershocks were located down-dip of the high-slip areas and laid in stress shadows. We deduce that the aftershocks may be controlled by the background tectonic stress field, and may be related to the velocity-strengthening zones.

scholarly journals ESTIMATION OF STATIC COULOMB STRESS CHANGE AND STRONG MOTION SIMULATION FOR JIUZHAIGOU 7.0 EARTHQUAKE BASE ON SENTINEL-1 INSAR DATA INVERSION

2018 ◽  
Vol XLII-3 ◽  
pp. 1533-1537
Author(s):  
W. H. Shen ◽  
Y. Luo ◽  
Q. S. Jiao
Keyword(s):  
Ground Motion ◽  
Static Stress ◽  
Peak Ground Velocity ◽  
Coseismic Deformation ◽  
Coulomb Stress ◽  
Slip Model ◽  
Ground Acceleration ◽  
Low Level ◽  
Finite Fault ◽  
Stress Changes

On August 8, 2017, an earthquake of M&amp;thinsp;7.0 occurred at Jiuzhaigou. Based on the Sentinel-1 satellite InSAR data, we obtained coseismic deformation field and inverted the source slip model. Results show that this event is dominated by strike slip, and the total released seismic moment is 8.06&amp;thinsp;&amp;times;&amp;thinsp;1018&amp;thinsp;Nm, equivalent to an earthquake of <i>M<sub>w</sub></i>&amp;thinsp;~&amp;thinsp;6.57. We calculated static stress changes along strike and dip direction, and the static stress analysis show that the average stress drop are at low level, which may be responsible for the low level of ground motion during Jiuzhaigou earthquake. The coseismic Coulomb stress changes are calculated base on the inverted slip model, which revealed that 82.59&amp;thinsp;% of aftershocks are located in the Coulomb stress increasing area, 78.42&amp;thinsp;% of total aftershocks may be triggered by the mainshock aftershock, indicating that the mainshock has a significant triggering effect on the subsequent aftershocks. Based on stochastic finite fault model, we simulated regional peak ground acceleration (PGA), peak ground velocity (PGV) and the intensity, and results could capture basic features associated with the ground motion patterns. Moreover, the simulated results reflect the obvious rupture directivity effect.

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