Major Earthquake Events Research Articles

Earthquake Macro-zonation Based Peak Ground Acceleration, Modified Mercalli Intensity, And Type of Rocks around Matano Fault

This study aims to determine earthquake vulnerable zones. We conducted research on earthquake macro-zonation based on PGA, Modified Mercalli Intensity (MMI), and type of rocks around Matano Fault in the area of 1.60 S to 2.990 S and 120.50 E to 122.470 E. We have acquired Maximum PGA and Modified Mercalli Intensity (MMI) for each observation point on the ground from the four major earthquake events. The empirical model is used due to lack of acceleration data recorded. We tried some empirical methods, but the McGuire method is found to be acceptable for this area. The result gives the maximum variation of PGA which is ranged between 18.40 - 363.54 gals. While the variation of MMI using empirical Wald attenuation gives values ranging from 2.9 - 7.7 MMI. The most vulnerable zone is located around Sorowako city with PGA value of 326.55 gals and MMI value of 7.5 MMI. This area is between ultra-basic rock and metamorphic rock formation. The vulnerable zone is near largest earthquake 6.2 M on 15-02-2011.

Three-Dimensional Response of Neighboring Buildings Sitting on Pile Foundations to Seismic Pounding

Seismic pounding occurs when the separation gap between buildings and structures is not wide enough, particularly during major earthquake events; this can cause them to collide, causing local damage or, in extreme cases, collapse. This study investigated the impact that this separation gap has on the seismic response of midrise buildings supported on piles while considering seismic soil–pile–structure interaction (SSPSI). To achieve this aim, three 15-story reinforced concrete buildings sitting on pile foundations and with five different separation gaps under excitations from the 1994 Northridge and 1995 Kobe earthquakes were numerically simulated. This study used three-dimensional numerical modeling to simultaneously capture the effects of seismic pounding and SSPSI. Because the considered structure, pile foundation, and soil deposit are three-dimensional in nature, the adopted three-dimensional numerical modeling can provide a more realistic simulation to capture the seismic behavior of the system. The nonlinear behavior of structural elements was included, and the dynamic soil properties were obtained from field data and backbone curves. A contact pair interface with small-sliding surface-to-surface formulation between buildings was used to capture possible seismic pounding, and contact interfaces with a finite-sliding formulation were used to simulate the interaction between the piles and the soil. The results, including lateral building deflections, interstory drifts, structural shear forces, foundation rocking, lateral pile deflections, and the distributions of bending moments and shear forces of the piles, are presented and discussed. The findings of this study will give engineers a better insight into the possible effects of seismic pounding on the seismic performance of buildings, and the response of end-bearing piles in soft soils.

Medium-Term Health of Seniors Following Exposure to a Natural Disaster.

The article aims to describe the medium-term impacts of a major earthquake event (Chile, February 27, 2010) on 26 seniors. The authors adopted a qualitative study approach. Data obtained using the Impact of Event Scale–Revised (IES-R) show the presence of manifestations of posttraumatic stress in the majority of respondents. In addition, data collected in interviews demonstrated a progressive deterioration of the health of respondents over a period of 4 years following the disaster. Seniors are particularly vulnerable to the effects of material loss, emotional stress, and postdisaster health complications. These impacts are exacerbated by low economic status. Furthermore, broader research is necessary involving elderly living in poverty who have survived natural disasters and others without such experiences, in order to better identify and differentiate between health complications associated with exposure to disaster events and those linked more strictly with natural aging processes.

Seismic response of a historic church considering pounding phenomena

The vulnerability of historic masonry structures and monuments under seismic loading including churches has been confirmed during major recent earthquake events. The current research focuses on pounding effects on masonry structures, a vulnerability factor that even though it is considered to be significant for the response of adjacent reinforced concrete structures is rarely taken into account for masonry structures in current engineering practice. The central church, the so called “Katholikon”, of the Kaisariani Monastery located in Athens, Greece, is selected as a case study of a historic structure that may present pounding phenomena because of its contact with an adjacent ecclesiastic structure, added during the 16th–17th centuries. The Katholikon, one of the finest Byzantine monuments of Greece, is a Byzantine crossed-dome church constructed during two separate structural phases build in contact during the 10th/11th and 16th/17th centuries, respectively. Based on data collected with the aid of an extensive experimental investigation of the monument different modeling approaches and different analysis methods were applied including time history and response spectrum analysis using the finite element method. The results indicate that pounding significantly affects the seismic response, while an individual analysis considering pounding is needed to provide accurate results. Also significant differences are observed between the results obtained from the response spectrum and the time history analysis suggesting that the usually applied response spectrum analysis does not always provide conservative results of the actual behavior.

Men’s Help-Seeking and Health in Natural Disaster Contexts

OBJECTIVE: The study examines masculinity practices, in both their positive and negative aspects, in terms of their influence on men’s help-seeking in the context of a natural disaster, in particular the rejection of psychosocial assistance.METHODOLOGY: Qualitative study of a small sample of voluntary participants constituted of male survivors of a major earthquake and tsunami event in 2010 in Chile.RESULTS: It appears that norms of hegemonic masculinity predominated in men’s emotional responses to the disaster event, with both positive and negative consequences. Family relationships, mutual assistance in the community, and the passage of time emerge as the principal factors of healing for men since the catastrophe.DISCUSSION: An understanding of men’s beliefs and attitudes is, therefore, essential to any inclusive assessment of the efficacy and quality of the various services offered to populations exposed to natural disaster events.

Temporal and spatial distributions of precursory seismicity rate changes in the Thailand-Laos-Myanmar border region: implication for upcoming hazardous earthquakes

To study the prospective areas of upcoming strong-to-major earthquakes, i.e., M w ≥ 6.0, a catalog of seismicity in the vicinity of the Thailand-Laos-Myanmar border region was generated and then investigated statistically. Based on the successful investigations of previous works, the seismicity rate change (Z value) technique was applied in this study. According to the completeness earthquake dataset, eight available case studies of strong-to-major earthquakes were investigated retrospectively. After iterative tests of the characteristic parameters concerning the number of earthquakes (N) and time window (T w ), the values of 50 and 1.2 years, respectively, were found to reveal an anomalous high Z-value peak (seismic quiescence) prior to the occurrence of six out of the eight major earthquake events studied. In addition, the location of the Z-value anomalies conformed fairly well to the epicenters of those earthquakes. Based on the investigation of correlation coefficient and the stochastic test of the Z values, the parameters used here (N = 50 events and T w = 1.2 years) were suitable to determine the precursory Z value and not random phenomena. The Z values of this study and the frequency-magnitude distribution b values of a previous work both highlighted the same prospective areas that might generate an upcoming major earthquake: (i) some areas in the northern part of Laos and (ii) the eastern part of Myanmar.

Preearthquake anomalous ionospheric signatures observed at low‐mid latitude Indian station, Delhi, during the year 2015 to early 2016: Preliminary results

AbstractWe have analyzed five major earthquake events measuring greater than 6 on Richter scale (M > 6) that occurred during the year 2015 to early 2016, affecting Indian region ionosphere, using F2 layer critical parameters (foF2, hmF2) obtained using Digisonde from a low‐mid latitude Indian station, Delhi (28.6°N, 77.2°E, 19.2°N geomagnetic latitude, 42.4°N dip). Normal day‐to‐day variability occurring in ionosphere is segregated by calculating F2 layer critical frequency and peak height variations (ΔfoF2, ΔhmF2) from the normal quiet time behavior apart from computing interquartile range. We find that the ionospheric F2 region across Delhi by and large shows some significant perturbations 3–4 days prior to these earthquake events, resulting in a large peak electron density variation of ~200%. These observed perturbations indicate towards a possibility of seismo‐ionospheric coupling as the solar and geomagnetic indices were normally quiet and stable during the period of these events. It was also observed that the precursory effect of earthquake was predominantly seen even outside the earthquake preparation zone, as given by Dobrovolsky et al. (1979). The thermosphere neutral composition (O/N2) as observed by Global Ultraviolet Imager, across Delhi, during these earthquake events does not show any marked variation. Further, the effect of earthquake events on ionospheric peak electron density is compared to the lower atmosphere meteorological phenomenon of 2015 sudden stratospheric warming event.

The heritage problem: is current policy on earthquake-prone heritage buildings too costly?

Earthquakes are a major hazard around the world (Bjornerud, 2016). A recent example is New Zealand, where three major earthquake events occurred within a six-year period. The 2010–11 earthquakes in Canterbury, centred close to the city of Christchurch, led to 185 fatalities, mainly due to two collapsed buildings and crumbling facades (Crampton and Meade, 2016). In addition, the rebuild of Christchurch after the earthquakes cost $40 billion (English, 2013), a large sum for a small country. Subsequent large earthquakes occurred in 2013 in Seddon (close to Wellington) and in 2016 in Kaiköura.

Evaluation of an enhanced FS method for finding the initiation time of earthquake-induced landslides

In this paper, an examination of an enhanced FS method used for finding the initiation time of earthquake-induced landslides is presented. Validation was conducted via comparisons between the predicted and reported results of a benchmark site subjected to two major earthquake events: at Chi-Chi in 1999 (7.6 Mw) and Meinong in 2016 (6.4 Mw). To further validate the applicability of the ground motions utilized in this study, a finite element analysis was also carried out. Based on the results, satisfactory agreement between the predictions obtained by the enhanced FS method and the observed results in terms of the landslide initiation time was realized. Conclusions drawn from the study show that (a) the enhanced FS method can be both efficient and practical in finding the likely initiation time of a landslide, and it was found that the initiation time of the Tsaoling landslide during the Chi-Chi earthquake lay between 37.5 and 38.5 s; (b) when validating the enhanced FS method, the friction angle of 38.5o obtained from direct shear tests rather than a smaller value of 20.8o obtained from rotary-shear high-velocity friction experiments, led to a more appropriate results; and (c) the failure surface obtained by finite element codes was satisfactory when compared to the observed result.

Predictive models for post disaster shelter needs assessment

The assessment of shelter needs of displaced people in the aftermath of major earthquake events is one the main challenges that emergency responders currently have to face. Based on the scale of the disaster, the short-term shelter demand can turn into a temporary housing need for displaced population, which is a local government responsibility. The study presented in this paper is focused on a critical review of currently available methodologies and corresponding software packages that were developed specifically for estimating the number of displaced people and those who will most likely seek public sheltering and will need temporary housing. The main features and shortcomings of such tools are highlighted and interpreted with a view to future improvement and application in the disaster management field. Two software tools, ERGO-EQ and HAZUS-MH, have been identified as more exhaustive in considering all the different variables involved in the shelter needs estimation. For this reason, this study also includes a full application of those two software tools to a real case study. Specifically, the modelling of the February 22nd, 2011 Christchurch earthquake is presented, in which hazard, vulnerability and exposure (both physical and social) were characterized over a specific area of Christchurch urban area as input to the aforementioned software tools. The employed tools yielded different results in terms of dislocated people and shelter needs estimates, for which a brief discussion is presented on possible ways to improve and to better reflect the local conditions, in order to produce more realistic outputs.

Waves of destruction in the East Indies: the Wichmann catalogue of earthquakes and tsunami in the Indonesian region from 1538 to 1877

Abstract The two volumes of Arthur Wichmann's Die Erdbeben Des Indischen Archipels [ The Earthquakes of the Indian Archipelago ] (1918 and 1922) document 61 regional earthquakes and 36 tsunamis between 1538 and 1877 in the Indonesian region. The largest and best documented are the events of 1770 and 1859 in the Molucca Sea region, of 1629, 1774 and 1852 in the Banda Sea region, the 1820 event in Makassar, the 1857 event in Dili, Timor, the 1815 event in Bali and Lombok, the events of 1699, 1771, 1780, 1815, 1848 and 1852 in Java, and the events of 1797, 1818, 1833 and 1861 in Sumatra. Most of these events caused damage over a broad region, and are associated with years of temporal and spatial clustering of earthquakes. The earthquakes left many cities in ‘rubble heaps’. Some events spawned tsunamis with run-up heights >15 m that swept many coastal villages away. 2004 marked the recurrence of some of these events in western Indonesia. However, there has not been a major shallow earthquake (M≥8) in Java and eastern Indonesia for the past 160 years. During this time of relative quiescence, enough tectonic strain energy has accumulated across several active faults to cause major earthquake and tsunami events, such as those documented in the historical records presented here. The disaster potential of these events is much greater now than in the past due to exponential growth in population and urbanization in areas destroyed by past events. Supplementary material: Translation of the catalogues into English, scanned PDFs of the original catalogues and geographical locations of most place names found in the catalogue (as a KMZ file) are available at https://dx.doi.org/10.6084/m9.figshare.c.2860405.v1

Deformation estimation of an earth dam and its relation with local earthquakes, by exploiting multitemporal synthetic aperture radar interferometry: Mornos dam case (Central Greece)

Monitoring dam performance is a critical parameter in maintaining a safe dam. Safety concerns include seepage, internal erosion, and seismic issues in the case that the dam is located in high seismic hazard areas. Seismic considerations for dam safety among others includes the expected dam’s performance during seismic events. The scope of this research work concerns the capability to record potential deformation on the Mornos earth dam (central Greece) induced by major earthquake events that occurred in the broader area. For this purpose, a hybrid interferometry synthetic aperture radar (InSAR) method was applied using elements of conventional differential InSAR, short baseline interferometry approaches, and persistent scatterers interferometry. A time series of ascending and descending acquisitions of active microwave instrument/ERS-1 and 2 and advanced synthetic aperture radar/ENVISAT scenes covering the period from 1993 to 2010 were interferometrically combined. Five very strong seismic events with epicenters close to the dam, at the same period, were considered as potential sources of deformation. The lake’s water surface elevation was also considered as an additional factor of induced deformation. Results show a maximum deformation rate of ∼10 cm along the line of sight for the whole period. Although the observed deformation appears to be due to changes in water level following a particular pattern, this is interrupted over time, and these interruptions coincide in time with specific seismic events.

Nonlinear Seismic Analysis of Masonry Infill RC Buildings with Eccentric Bracings at Soft Storey Level

Eccentric bracings are used in steel structures for long time where it serves as lateral load resisting system and improve strength and stiffness of frame along with effective energy dissipation. In the present study, eccentric bracings are used as a means to reduce soft storey effect in masonry infill reinforced concrete (RC) building. Masonry infill buildings with open first storey are usual choice for almost every general multi-storey construction in India, despite the building's palpable vulnerability to strong ground motion earthquakes. Among other strengthening methods, eccentric bracings could be an advantageous scheme as it provides lateral stiffness and ductility to structure with greater economy and also provides free space for commuting of vehicle at soft storey level. It has been seen that introduction of soft storey in building leads to concentration of damage in that storey while the building suffers only slight damage. Hence, eccentric bracings in soft storey need to be designed in such a way that they act as fuse during major earthquake events. The seismic performance of eccentric bracings for a seven storey building located in Indian seismic zone – V as per Indian standard code 1893-2002 are investigated using nonlinear static pushover analysis. A parametric study involving parameters such as shape of eccentric bracing, area of section, amount of eccentricity etc. are performed for selecting the type of eccentric bracing. The results of pushover analysis, reported in terms of storey drift demand and collapse fragility curve, showed that buildings with eccentric bracings have lower drift demand and probability of collapse.

Comparative Analysis of Existing Tools for Assessment of Post-Earthquake Short-Term Lodging Needs

The assessment of shelter needs aimed at displaced population in the aftermath of major earthquake events is one the main challenges that emergency responders currently have to face. The study presented here is focused on a critical review of currently available methodologies and software packages that were developed specifically to estimate the number of displaced people and those who will most likely seek public sheltering and will need temporary housing. The main features and shortcomings of such tools are shown.

April‐25‐2015 Nepal Mw7.8 Seismogenic Process Analysis and Post‐Quake Trend Prediction

AbstractBased on the brittle failure theory of multiple locked patches in a seismogenic fault system and interplate seismic zoning principle proposed by the authors of this paper, the Islamabad–Kathmandu seismic zone is defined. Through seismogenic period definition and main shock event recognition, the seismogenic process of major/great earthquakes in this seismic zone is analyzed and the future trend of earthquake occurrence is predicted. The results show that the Islamabad–Kathmandu seismic zone is an Mw8.3∼8.6 earthquake hazard zone, and has undergone at least three complete seismogenic periods; the Nepal Mw7.8 earthquake on April 25, 2015 was a representative major earthquake event in the current seismogenic period when the damage of the third locked patch was accumulated to the peak strength point; After the Mw7.3 earthquake in Nepal on May 12, 2015, this seismic zone is already in another critical state of the current seismogenic period, and an Mw8.0∼8.2 earthquake would occur in short‐middle term.

Tien Shan Geohazards Database: Earthquakes and landslides

In this paper we present new and review already existing landslide and earthquake data for a large part of the Tien Shan, Central Asia. For the same area, only partial databases for sub-regions have been presented previously. They were compiled and new data were added to fill the gaps between the databases. Major new inputs are products of the Central Asia Seismic Risk Initiative (CASRI): a tentative digital map of active faults (even with indication of characteristic or possible maximum magnitude) and the earthquake catalogue of Central Asia until 2009 that was now updated with USGS data (to May 2014). The new compiled landslide inventory contains existing records of 1600 previously mapped mass movements and more than 1800 new landslide data. Considering presently available seismo-tectonic and landslide data, a target region of 1200km (E–W) by 600km (N–S) was defined for the production of more or less continuous geohazards information. This target region includes the entire Kyrgyz Tien Shan, the South-Western Tien Shan in Tajikistan, the Fergana Basin (Kyrgyzstan, Tajikistan and Uzbekistan) as well as the Western part in Uzbekistan, the North-Easternmost part in Kazakhstan and a small part of the Eastern Chinese Tien Shan (for the zones outside Kyrgyzstan and Tajikistan, only limited information was available and compiled).On the basis of the new landslide inventory and the updated earthquake catalogue, the link between landslide and earthquake activity is analysed. First, size–frequency relationships are studied for both types of geohazards, in terms of Gutenberg–Richter Law for the earthquakes and in terms of probability density function for the landslides. For several regions and major earthquake events, case histories are presented to outline further the close connection between earthquake and landslide hazards in the Tien Shan. From this study, we concluded first that a major hazard component is still now insufficiently known for both types of geohazards – and even totally unknown for most giant landslides: the time information. Thus, dating rockslides and any large mass movement is a crucial factor in order to better constrain related hazards. Second, we highlight the role of coupled hazards in the Tien Shan – inside the mountain range the largest disasters were caused by earthquake-triggered landslides and massive earth flows. Therefore, it is of prime importance for these mountain regions to complement single hazard assessment by coupled hazard scenarios. On the basis of these scenarios, risk evaluations may then be completed considering direct impacts on artificial dams, hydropower schemes, mining and road infrastructure as well as remote effects from possible dam breaches and mobilisation of mining and nuclear waste storages. Basic hazard and risk components are partly analysed in this paper and partly in a companion paper ‘Tien Shan geohazards database: Landslide susceptibility and impacts’.

Soil Liquefaction–Induced Uplift of Underground Structures: Physical and Numerical Modeling

AbstractUnderground structures located in liquefiable soil deposits are susceptible to floatation following a major earthquake event. Such failure phenomenon generally occurs when the soil liquefies and loses its shear resistance against the uplift force from the buoyancy of the underground structure. Numerical modeling accompanied with centrifuge experiments with shallow circular structures has been carried out to investigate the floatation failure at different buried depths of the structure. The influence of the magnitude of input sinusoidal earthquake shaking was also studied. Both numerical and experimental results showed matching uplift response of the structures and acceleration and pore-pressure measurements in the liquefied soil deposit. A higher uplift displacement of the structure was observed for shallower buried depth, thereby indicating the influence of overlying soil weight against floatation. Results also showed that the structures commenced floatation in the presence of high excess pore pr...

The progress of emergency response and rescue in China: a comparative analysis of Wenchuan and Lushan earthquakes

Earthquake emergency response and rescue (ERR) is a global challenge, but especially in developing countries. As a large earthquake-prone developing country, China’s experiences and lessons in ERR can provide a useful reference for other developing countries. In this article, China’s ERR progress is summarized by comparatively analyzing the Wenchuan and Lushan earthquakes, two major recent earthquake events in Sichuan Province. From a comprehensive investigation of the research, it can be concluded that emergency response speed, inter-organizational coordination, and relief resource mobilization are the three critical ERR indicators which can be further subdivided into sixteen sub-indicators. Using these indicators, the Wenchuan and Lushan earthquake ERR processes were comprehensively compared based on data collected from observations and interviews. The results showed that the response and rescue efforts at the Lushan earthquake were faster, more coordinated, and more orderly than those at the Wenchuan earthquake. In addition, the unified earthquake ERR system, the people-oriented principle, and the information disclosure mechanism were examined, which also revealed several major shortcomings, such as deficits in the adaptability to relief technologies, the lack of coordination between rescue organizations, and the lack of capabilities in the local communities. Finally, several recommendations are given for the practical improvement of and future research into the establishment of an effective ERR.

Application of Reliability-Based Robustness Assessment of Steel Moment Resisting Frame Structures under Post-Mainshock Cascading Events

This paper proposes a reliability-based framework for quantifying structural robustness considering the occurrence of a major earthquake (mainshock) and subsequent cascading hazard events, such as aftershocks that are triggered by the mainshock. These events can significantly increase the probability of failure of buildings, especially for structures that are damaged during the mainshock. The application of the proposed framework is exemplified through three numerical case studies. The case studies correspond to three SAC steel moment frame buildings of three, nine, and 20 stories, which were designed to pre-Northridge codes and standards. Two-dimensional nonlinear finite-element models of the buildings are developed with the Open System for Earthquake Engineering Simulation framework (OpenSees), using a finite length plastic hinge beam model and a bilinear constitutive law with deterioration, and are subjected to multiple mainshock-aftershock seismic sequences. For the three buildings analyzed herein, it is shown that the structural reliability under a single seismic event can be significantly different from that under a sequence of seismic events. The reliability based robustness indicator shows that the structural robustness is influenced by the extent to which a structure can distribute damage.

Seismic Risk of Inter-urban Transportation Networks

The paper presents a holistic approach for assessing and managing the seismic risk and potential loss in inter-urban highway networks in earthquake-prone areas. The vulnerability of all elements of the intercity transportation system (i.e., roads, bridges, abutments, retaining walls, and tunnels) is assessed considering the interdependency among the structural, transportational and geotechnical components of the network under different seismic scenarios. Both the direct earthquake-induced damage, as well as the indirect socio-economic loss attributed to reduced network functionality are taken into account in an explicit and transparent formulation that is then displayed in space through an ad-hoc developed GIS-based software. The methodology and the decision-making tools developed are adequately modular, for them to be utilized after appropriate adaptation by local authorities in identifying, prior to a major earthquake event, those vulnerable components of their network whose failure may have a disproportional socio-economic impact. In this way, a rational and effective emergency plan can be deployed to minimize potential human, social and financial loss after a future earthquake. The outline of a foreseen application is also presented for the case of the road network of the Region of Western Macedonia in Greece. Through this pilot application, the methodology is to be optimized in real conditions before being cast in the form of a fully parameterised seismic risk tool, to be used in other earthquake prone areas as well.