Nonparametric Assessment of Aftershock Clusters of the Maule Earthquake Mw = 8.8

2021 ◽  
Vol 11 (4) ◽  
pp. 623-638
Author(s):  
Javier E. Contreras-Reyes
Keyword(s):  
Maule Earthquake

Evolution of seismic design codes of highway bridges in Chile

2021 ◽  
pp. 875529302098801
Author(s):  
José Wilches ◽  
Hernán Santa Maria ◽  
Roberto Leon ◽  
Rafael Riddell ◽  
Matías Hube ◽  
...  
Keyword(s):  
Seismic Design ◽  
Failure Modes ◽  
Highway Bridges ◽  
Design Codes ◽  
Seismic Codes ◽  
Analysis And Design ◽  
Residual Displacements ◽  
Shear Keys ◽  
Maule Earthquake ◽  
2010 Maule Earthquake

Chile, as a country with a long history of strong seismicity, has a record of both a constant upgrading of its seismic design codes and structural systems, particularly for bridges, as a result of major earthquakes. Recent earthquakes in Chile have produced extensive damage to highway bridges, such as deck collapses, large transverse residual displacements, yielding and failure of shear keys, and unseating of the main girders, demonstrating that bridges are highly vulnerable structures. Much of this damage can be attributed to construction problems and poor detailing guidelines in design codes. After the 2010 Maule earthquake, new structural design criteria were incorporated for the seismic design of bridges in Chile. The most significant change was that a site coefficient was included for the estimation of the seismic design forces in the shear keys, seismic bars, and diaphragms. This article first traces the historical development of earthquakes and construction systems in Chile to provide a context for the evolution of Chilean seismic codes. It then describes the seismic performance of highway bridges during the 2010 Maule earthquake, including the description of the main failure modes observed in bridges. Finally, this article provides a comparison of the Chilean bridge seismic code against the Japanese and United States codes, considering that these codes have a great influence on the seismic codes for Chilean bridges. The article demonstrates that bridge design and construction practices in Chile have evolved substantially in their requirements for the analysis and design of structural elements, such as in the definition of the seismic hazard to be considered, tending toward more conservative approaches in an effort to improve structural performance and reliability for Chilean bridges.

Nature and tectonic significance of co-seismic structures associated with the Mw 8.8 Maule earthquake, central-southern Chile forearc

2011 ◽  
Vol 33 (5) ◽  
pp. 891-897 ◽  
Author(s):  
C. Arriagada ◽  
G. Arancibia ◽  
J. Cembrano ◽  
F. Martínez ◽  
D. Carrizo ◽  
...  
Keyword(s):  
Southern Chile ◽  
Tectonic Significance ◽  
Maule Earthquake

scholarly journals Determination of the complex frequencies for the normal modes below 1mHz after the 2010 Maule and 2011 Tohoku earthquakes

2014 ◽  
Vol 56 (5) ◽  
Author(s):  
Hao Ding ◽  
Wen-Bin Shen
Keyword(s):  
Time Series ◽  
Normal Modes ◽  
Power Spectra ◽  
Tohoku Earthquake ◽  
Superconducting Gravimeter ◽  
Width Ratio ◽  
Maule Earthquake ◽  
Attenuation Models ◽  
First Time

<p>Based upon SG (superconducting gravimeter) records, the autoregressive method proposed by Chao and Gilbert [1980] is used to determine the frequencies of the singlets of seven spheroidal modes (<sub>0</sub>S<sub>2</sub>, <sub>2</sub>S<sub>1</sub>, <sub>0</sub>S<sub>3</sub>, <sub>0</sub>S<sub>4</sub>, <sub>1</sub>S<sub>2</sub>, <sub>0</sub>S<sub>0</sub>, and <sub>3</sub>S<sub>1</sub>) and the degenerate frequencies of three toroidal modes (<sub>0</sub>T<sub>2</sub>, <sub>0</sub>T<sub>3</sub>, and <sub>0</sub>T<sub>4</sub>) below 1 mHz after two recent huge earthquakes, the 2010 Mw8.8 Maule earthquake and the 2011 Mw9.1 Tohoku earthquake. The corresponding quality factor <em>Q</em>s are also determined for those modes, of which the <em>Q</em>s of the five singlets of <sub>1</sub>S<sub>2</sub> and the five singlets (<em>m</em>=0, <em>m</em>=±2, and <em>m</em>=±3) of <sub>0</sub>S<sub>4</sub> are estimated for the first time using the SG observations. The singlet <em>m</em>=0 of <sub>3</sub>S<sub>1</sub> is clearly observed from the power spectra of the SG time series without using other special spectral analysis methods or special time series from pole station records. In addition, the splitting width ratio <em>R</em> of <sub>3</sub>S<sub>1</sub> is 0.99, and consequently we conclude that <sub>3</sub>S<sub>1</sub> is normally split. The frequencies and <em>Q</em>s of the modes below 1mHz may contribute to refining the 3D density and attenuation models of the Earth.</p>

scholarly journals Illuminating subduction zone rheological properties in the wake of a giant earthquake

2019 ◽  
Vol 5 (12) ◽  
pp. eaax6720 ◽  
Author(s):  
Jonathan R. Weiss ◽  
Qiang Qiu ◽  
Sylvain Barbot ◽  
Tim J. Wright ◽  
James H. Foster ◽  
...  
Keyword(s):  
Subduction Zone ◽  
Subduction Zones ◽  
Three Dimensional ◽  
Surface Strain ◽  
Postseismic Deformation ◽  
Crust And Upper Mantle ◽  
Plate Convergence ◽  
Maule Earthquake ◽  
History Of ◽  
Dependent Viscosity

Deformation associated with plate convergence at subduction zones is accommodated by a complex system involving fault slip and viscoelastic flow. These processes have proven difficult to disentangle. The 2010 Mw 8.8 Maule earthquake occurred close to the Chilean coast within a dense network of continuously recording Global Positioning System stations, which provide a comprehensive history of surface strain. We use these data to assemble a detailed picture of a structurally controlled megathrust fault frictional patchwork and the three-dimensional rheological and time-dependent viscosity structure of the lower crust and upper mantle, all of which control the relative importance of afterslip and viscoelastic relaxation during postseismic deformation. These results enhance our understanding of subduction dynamics including the interplay of localized and distributed deformation during the subduction zone earthquake cycle.

scholarly journals Contrasting seismic risk for Santiago, Chile, from near-field and distant earthquake sources

2019 ◽  
Author(s):  
Ekbal Hussain ◽  
John R. Elliott ◽  
Vitor Silva ◽  
Mabé Vilar-Vega ◽  
Deborah Kane
Keyword(s):  
Low Income ◽  
Seismic Risk ◽  
Near Field ◽  
Active Faults ◽  
Rapid Expansion ◽  
Seismic Risk Analysis ◽  
Earthquake Sources ◽  
Maule Earthquake ◽  
The City ◽  
Distant Earthquake

Abstract. More than half of all the people in the world now live in dense urban centres. The rapid expansion of cities, particularly in low-income nations, has enabled the economic and social development of millions of people. However, many of these cities are located near active tectonic faults that have not produced an earthquake in recent memory, raising the risk of losing the hard-earned progress through a devastating earthquake. In this paper we explore the possible impact that earthquakes can pose to the city of Santiago in Chile from various potential near-field and distant earthquake sources. We use high resolution stereo satellite imagery and derived digital elevation models to accurately map the trace of the San Ramón Fault, a recently recognised active fault located along the eastern margins of the city. We use scenario based seismic risk analysis to compare and contrast the estimated damage and losses to the city from several potential earthquake sources and one past event, comprising (i) rupture of the San Ramón Fault, (ii) a hypothesised buried shallow fault beneath the centre of the city, (iii) a deep intra-slab fault, and (iv) the 2010 Mw 8.8 Maule earthquake. We find that there is a strong magnitude-distance trade-off in terms of damage and losses to the city, with smaller magnitude earthquakes on more local faults, in the magnitude range 6–7.5, producing 9 to 17 times more damage to the city and estimated fatalities compared to the great magnitude 8+ earthquakes located offshore on the subduction zone. Our calculations for this part of Chile show that unreinforced masonry structures are the most vulnerable to these types of earthquake shaking. We identify particularly vulnerable districts, such as Ñuñoa, Santiago and Macul, where targeted retrofitting campaigns would be most effective at reducing potential economic and human losses. Due to the potency of near-field earthquake sources demonstrated here, our work highlights the importance of also identifying and considering proximal minor active faults for cities in seismic zones globally, in addition to the more major distant large fault zones that are typically focused on in the assessment of hazard.

scholarly journals Risk Factors and Perceived Restoration in a Town Destroyed by the 2010 Chile Tsunami

2016 ◽  
Author(s):  
Carolina Martínez ◽  
Octavio Rojas ◽  
Paula Villagra ◽  
Rafael Aránguiz ◽  
Katia Sáez-Carrillo
Keyword(s):  
Risk Factors ◽  
Principal Component ◽  
Large Earthquake ◽  
Similar Degree ◽  
Restorative Environments ◽  
Reconstruction Process ◽  
Maule Earthquake ◽  
The 2010 Chile Tsunami ◽  
Chile Tsunami ◽  
Post Disaster

Abstract. A large earthquake and tsunami took place in February 2010, affecting a significant part of the Chilean coast (Maule earthquake (Mw = 8.8). Dichato (37° S), a small town located on Coliumo Bay, was one of the most devastated coastal places and is currently under reconstruction. Therefore, the risk factors which explain the disaster at that time as well as perceived restoration 6 years after the event were analyzed in the present paper. Numerical modeling of the 2010 Chile tsunami with four nested grids was applied to estimate the hazard. Physical, socio-economic and educational dimensions of vulnerability were analyzed for pre- and post-disaster conditions. A perceived restoration study was performed to assess the effects of reconstruction on the community and a principal component analysis was applied for post-disaster conditions. The vulnerability factors that best explained the extent of the disaster were housing conditions, low household incomes and limited knowledge about tsunami events, which conditioned inadequate reactions to the emergency. These factors still constitute the same risks as a result of the reconstruction process, establishing that the occurrence of a similar event would result in a similar degree of disaster. For post-earthquake conditions, it was determined that all neighborhoods have the potential to be restorative environments soon after a tsunami. However, some neighborhoods are still located in areas devastated by the 2010 tsunami and present a high vulnerability to future tsunamis. Therefore, it may be stated that these areas will probably be destroyed again in case of future events.

Assessing disaster capitalism in post-disaster processes in Chile: neoliberal reforms and the role of the corporate class

2020 ◽  
Vol 29 (6) ◽  
pp. 831-847
Author(s):  
Vicente Sandoval ◽  
Claudia Gonzalez-Muzzio ◽  
Carlos Villalobos ◽  
Juan Pablo Sarmiento ◽  
Gabriela Hoberman
Keyword(s):  
Private Sector ◽  
Private Funding ◽  
Content Type ◽  
Neoliberal Reforms ◽  
Maule Earthquake ◽  
Disaster Capitalism ◽  
2010 Maule Earthquake ◽  
Cross Case Analysis ◽  
Post Disaster

PurposeThis paper examines disaster capitalism in Chile, that is, the relationships between disasters and neoliberalism. It looks at two post-disaster dimensions: disasters as windows of opportunity to introduce political reforms and disasters as occasions for the corporate class to capitalize on such disasters.Design/methodology/approachTwo indices, disaster capitalism (DC) and post-disaster private involvement (PDPI), are proposed for cross-case analysis. They are based on legal records, institutional reports and economic data. The DC assesses the introduction of reforms following disasters, while PDPI evaluates the share of public-private funding used for recovery. Both indices are applied here to two disasters in Chile: the 2010 Maule earthquake, and the 2008 Chaitén volcanic eruption.FindingsResults show that the highly neoliberal Chilean context leaves limited space for new neoliberal reforms. Although recovery is implemented predominantly through the private sector, the state still assumes greater responsibility for recovery costs. Results also detect poor levels of participation from the private sector in accounting their efforts and making them publicly available. Likewise, the research suggests that neoliberal reforms become more likely after disasters. However, the preexisting politico-economic context matters. Finally, there is clearly a need for data systematization in post-disaster recovery.Originality/valueIn the Chilean context, the indices proved beneficial as a strategy for data collection and a method for scrutinizing the implications of neoliberal policy implemented in the wake of disasters, as well as in evaluating the role of the corporate class during recovery.

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.

Seismic Performance of Engineered Masonry Buildings in the 2010 Maule Earthquake

2012 ◽  
Vol 28 (1_suppl1) ◽  
pp. 385-406 ◽  
Author(s):  
Maximiliano Astroza ◽  
Ofelia Moroni ◽  
Svetlana Brzev ◽  
Jennifer Tanner
Keyword(s):  
Seismic Performance ◽  
Housing Construction ◽  
Masonry Buildings ◽  
Single Family ◽  
Similar Statement ◽  
Confined Masonry ◽  
Maule Earthquake ◽  
Extent Of Damage ◽  
2010 Maule Earthquake ◽  
Extensive Damage

Engineered masonry, namely reinforced and confined masonry, has been widely used for housing construction in Chile over the last few decades. Most one- and two-story single-family masonry dwellings did not experience any damage due to the 27 February 2010 Maule earthquake, with the exception of a few dwellings of pre-1970 vintage, which suffered moderate damage. A similar statement can be made for three- and four-story confined masonry buildings: a large majority of buildings remained undamaged. However, several reinforced and partially confined three- and four-story masonry buildings suffered extensive damage, and two three-story partially confined buildings collapsed. The key damage patterns and the causes of damage are discussed in the paper. The extent of damage observed in the field was correlated with calculated vulnerability indices, and relevant recommendations were made related to the design and construction practices.

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