Las viviendas subterráneas y el riesgo sísmico

Se estima que las viviendas subterráneas a lo largo del mundo albergan entre 40 y 60 millones de personas. Tras un análisis general de las tipologías de viviendas subterráneas, de su localización y de los factores que influyen en su desarrollo se ha introducido el análisis de la vulnerabilidad de este tipo de viviendas ante los riesgos naturales, cuestión que no ha sido estudiada exhaustivamente con anterioridad. Cabe destacar que la localización de las viviendas subterráneas a lo largo del mundo coincide en la mayor parte de los casos con regiones activas sísmicamente, por lo que se lleva a cabo una primera aproximación al estudio de la vulnerabilidad de las viviendas subterráneas frente al riesgo sísmico, teniendo como antecedente el terremoto de la región china de Shaanxi ocurrido en 1556, que afectó a grandes agrupaciones de viviendas subterráneas.

Local and global responses to disaster: #eqnz and the Christchurch earthquake

Building on innovative frameworks for analysing and visualising the tweet data available from Twitter, developed by the authors, this paper examines the patterns of tweeting activity that occurred during and after the Feb, 2011 Christchurch earthquake. Local and global responses to the disaster were organised around the pre-existing hashtag #eqnz, which averaged some 100 tweets per minute in the hours following the earthquake. The paper identifies the key contributors to the #eqnz network and shows the key themes of their messages. Emerging from this analysis is a more detailed understanding of Twitter and other social media as key elements in the overall ecology of the media forms used for crisis communication. Such uses point both to the importance of social media as a tool for affected communities to self-organise their disaster response and recovery activities, and as a tool for emergency management services to disseminate key information and receive updates from local communities.

Recovering from the earthquake : early childhood teachers and children collaboratively telling stories about their experiences

Purpose – Traumatic events can cause post-traumatic stress disorder due to the severity of the often unexpected events. The purpose of this paper is to reveal how conversations around lived experiences of traumatic events, such as the Christchurch earthquake in February 2011, can work as a strategy for people to come to terms with their experiences collaboratively. By encouraging young children to recall and tell of their earthquake stories with their early childhood teachers they can begin to respond, renew, and recover (Brown, 2012), and prevent or minimise more stress being developed. Design/methodology/approach – The study involved collecting data of the participating children taking turns to wear a wireless microphone where their interactions with each other and with teachers were video recorded over one week in November 2011. A total of eight hours and 21 minutes of footage was collected; four minutes and 19 seconds of that footage are presented and analysed in this paper. The footage was watched repeatedly and transcribed using conversation analysis methods (Sacks, 1995). Findings – Through analysing the detailed turn-taking utterances between teachers and children, the orderliness of the co-production of remembering is revealed to demonstrate that each member orients to being in agreement about what actually happened. These episodes of story telling between the teachers and children demonstrate how the teachers encourage the children to tell about their experiences through actively engaging in conversations with them about the earthquake. Originality/value – The conversation analysis approach used in this research was found to be useful in investigating aspects of disasters that the participants themselves remember as important and real. This approach offers a unique insight into understanding how the earthquake event was experienced and reflected on by young children and their teachers, and so can inform future policy and provision in post-disaster situations.

Living in a broken world : how young children's well-being is supported through playing out their earthquake experiences

The therapeutic value of play can be shown in spontaneous play situations following children’s experiences of traumatic events. Following the events of the Christchurch earthquakes in New Zealand in 2010 and 2011, an investigation was conducted of how children used the earthquake event as a catalyst in pretend play with peers and in discussions with teachers. Supporting children’s well-being is a focus area in New Zealand early childhood education as it is a strand of the national curriculum, Te Whāriki (Ministry of Education [MoE], 1996). In this article, children are observed engaging in pretend play episodes and with Learning Story books to explore personal reflections of the earthquake, prompting the children to make reference to things being ‘broken’ and needing 'fixing.' Analysis shows how the content of the pretend play experiences helped the children to come to terms with their experiences. Affording children time and interactional opportunities to play out and discuss traumatic experiences contributes to the psychological well-being of participants following a traumatic event.

Risk mitigation of post-earthquake fire in urban buildings

Post-earthquake fire (PEF) is considered one of the most high risk and complicated problems affecting buildings in urban areas and can cause even more damage than the earthquake itself. However, most standards and codes ignore the implications of PEF and so buildings are not normally designed with PEF in mind. What is needed is for PEF factors to be routinely scrutinized and codified as part of the design process. A systematic application is presented as a means of mitigating the risk of PEF in urban buildings. This covers both existing buildings, in terms of retrofit solutions, and those yet to be designed, where a PEF factor is proposed. To ensure the mitigation strategy meets the defined criteria, a minimum time is defined – the safety guaranteed time target – where the safety of the inhabitants in a building is guaranteed.

Australian nurses volunteering for the Sumatra-Andaman earthquake and tsunami of 2004 : a review of experience and analysis of data collected by the Tsunami Volunteer Hotline

This paper provides an outline of the work undertaken by nurses who participated in the relief effort as members of Australian medical teams during the Sumatra-Andaman earthquake and tsunami response. This profile is contrasted with the information provided by nurses who registered their interest in volunteering to help via the Australian Tsunami Hotline. The paper provides an overview of the skills and background of the nurses who provided information to the hotline and describes the range and extent of experience among this cohort of potential volunteers. This data is compared to nursing workforce data and internal rates of volunteering in Australia. The paper concludes that further research is necessary to examine the motivations of and disincentives for nurses to volunteer for overseas (disaster) work and, to develop an improved understanding within the discipline of the skills and experience required of volunteer responders. Further, it is argued that the development of standards for the collection of disaster health volunteer data would assist future responses and provide better tools for developing an improved understanding of disaster volunteering.

Estimates of lost material stock of buildings and roads due to the great east Japan earthquake and tsunami

This article describes research conducted for the Japanese government in the wake of the magnitude 9.0 earthquake and tsunami that struck eastern Japan on March 11, 2011. In this study, material stock analysis (MSA) is used to examine the losses of building and infrastructure materials after this disaster. Estimates of the magnitude of material stock that has lost its social function as a result of a disaster can indicate the quantities required for reconstruction, help garner a better understanding of the volumes of waste flows generated by that disaster, and also help in the course of policy deliberations in the recovery of disaster-stricken areas. Calculations of the lost building and road materials in the five prefectures most affected were undertaken. Analysis in this study is based on the use of geographical information systems (GIS) databases and statistics; it aims to (1) describe in spatial terms what construction materials were lost, (2) estimate the amount of infrastructure material needed to rehabilitate disaster areas, and (3) indicate the amount of lost material stock that should be taken into consideration during government policy deliberations. Our analysis concludes that the material stock losses of buildings and road infrastructure are 31.8 and 2.1 million tonnes, respectively. This research approach and the use of spatial MSA can be useful for urban planners and may also convey more appropriate information about disposal based on the work of municipalities in disaster-afflicted areas.

Classification and rating of strong-motion earthquake records

Ninety-two strong-motion earthquake records from the California region, U.S.A., have been statistically studied using principal component analysis in terms of twelve important standardized strong-motion characteristics. The first two principal components account for about 57 per cent of the total variance. Based on these two components the earthquake records are classified into nine groups in a two-dimensional principal component plane. Also a unidimensional engineering rating scale is proposed. The procedure can be used as an objective approach for classifying and rating future earthquakes.

Reassessing the earthquake hazard in Kerala based on the historical and current seismicity

Given the lack of proper constraints in understanding earthquake mechanisms in the cratonic interiors and the general absence of good quality database, here we reassess the seismic hazard in the province of Kerala, a part of the aEuro cent stable continental interioraEuro cent, based on an improved historical and instrumental database. The temporal pattern of the current seismicity suggests that > 60% of the microtremors in Kerala occurs with a time lag after the peak rainfall, indicating that hydroseismicity may be a plausible model to explain the low-level seismicity in this region. Further, an increment in overall seismicity rate in the region in the recent years is explained as due to increased anthropogenic activities, which includes changes in hydrological pathways as a consequence of rapid landscape changes. Our analyses of the historical database eliminate a few events that are ascribed to this region; this exercise has also led to identification of a few events, not previously noted. The improved historical database essentially suggests that the central midland region is more prone to seismic activity compared to other parts of Kerala. This region appears to have generated larger number of significant earthquakes; the most prominent being the multiple events (doublets) of 1856 and 1953, whose magnitudes are comparable to that of the 2000/2001 (central Kerala) events. Occurrences of these historical events and the recent earthquakes, and the local geology indicative of pervasive faulting as shown by widely distributed pseudotachylite veins suggest that the NNW-SSE trending faults in central midland Kerala may host discrete potentially active sources that may be capable of generating light to moderate size earthquakes. The frequency of earthquakes in central Kerala evident from the historical database requires that the seismic codes stipulated for this region are made mandatory.

Hebrew hymns and prayers after an earthquake, during the reign of George II (1727-1760)

Digital image

Seismic Tomography and Earthquake Mechanism Beneath the Central Fennoscandian Shield

The aim of this thesis was to study the seismic tomography structure of the earth s crust together with earthquake distribution and mechanism beneath the central Fennoscandian Shield, mainly in southern and central Finland. The earthquake foci and some fault plane solutions are correlated with 3-D images of the velocity tomography. The results are discussed in relation to the stress field of the Shield and with other geophysical, e.g. geomagnetic, gravimetric, tectonic, and anisotropy studies of the Shield. The earthquake data of the Fennoscandian Shield has been extracted from the Nordic earthquake parameter data base which was founded at the time of inception of the earthquake catalogue for northern Europe. Eight earlier earthquake source mechanisms are included in a pilot study on creating a novel technique for calculating an earthquake fault plane solution. Altogether, eleven source mechanisms of shallow, weak earthquakes are related in the 3-D tomography model to trace stresses of the crust in southern and central Finland. The earthquakes in the eastern part of the Fennoscandian Shield represent low-active, intraplate seismicity. Earthquake mechanisms with NW-SE oriented horizontal compression confirm that the dominant stress field originates from the ridge-push force in the North Atlantic Ocean. Earthquakes accumulate in coastal areas, in intersections of tectonic lineaments, in main fault zones or are bordered by fault lines. The majority of Fennoscandian earthquakes concentrate on the south-western Shield in southern Norway and Sweden. Onwards, epicentres spread via the ridge of the Shield along the west-coast of the Gulf of Bothnia northwards along the Tornio River - Finnmark fault system to the Barents Sea, and branch out north-eastwards via the Kuusamo region to the White Sea Kola Peninsula faults. The local seismic tomographic method was applied to find the terrane distribution within the central parts of the Shield the Svecofennian Orogen. From 300 local explosions a total of 19765 crustal Pg- and Sg-wave arrival times were inverted to create independent 3-D Vp and Vs tomographic models, from which the Vp/Vs ratio was calculated. The 3-D structure of the crust is presented as a P-wave and for the first time as an S-wave velocity model, and also as a Vp/Vs-ratio model of the SVEKALAPKO area that covers 700x800 km2 in southern and central Finland. Also, some P-wave Moho-reflection data was interpolated to image the relief of the crust-mantle boundary (i.e. Moho). In the tomography model, the seismic velocities vary smoothly. The lateral variations are larger for Vp (dVp =0.7 km/s) than for Vs (dVs =0.4 km/s). The Vp/Vs ratio varies spatially more distinctly than P- and S-wave velocities, usually from 1.70 to 1.74 in the upper crust and from 1.72 to 1.78 in the lower crust. Schist belts and their continuations at depth are associated with lower velocities and lower Vp/Vs ratios than in the granitoid areas. The tomography modelling suggests that the Svecofennian Orogen was accreted from crustal blocks ranging in size from 100x100 km2 to 200x200 km2 in cross-sectional area. The intervening sedimentary belts have ca. 0.2 km/s lower P- and S-wave velocities and ca. 0.04 lower Vp/Vs ratios. Thus, the tomographic model supports the concept that the thick Svecofennian crust was accreted from several crustal terranes, some hidden, and that the crust was later modified by intra- and underplating. In conclusion, as a novel approach the earthquake focal mechanism and focal depth distribution is discussed in relation to the 3-D tomography model. The schist belts and the transformation zones between the high- and low-velocity anomaly blocks are characterized by deeper earthquakes than the granitoid areas where shallow events dominate. Although only a few focal mechanisms were solved for southern Finland, there is a trend towards strike-slip and oblique strike-slip movements inside schist areas. The normal dip-slip type earthquakes are typical in the seismically active Kuusamo district in the NE edge of the SVEKALAPKO area, where the Archean crust is ca. 15-20 km thinner than the Proterozoic Svecofennian crust. Two near vertical dip-slip mechanism earthquakes occurred in the NE-SW junction between the Central Finland Granitoid Complex and the Vyborg rapakivi batholith, where high Vp/Vs-ratio deep-set intrusion splits the southern Finland schist belt into two parts in the tomography model.

Dental identification and aspects of medico-legal investigations of the Finnish victims of the Sumatra-Andaman earthquake on 26 December 2004

Tsunami waves of the Sumatra-Andaman earthquake on 26 December 2004 claimed approximately 230 000 lives and started the biggest identification operation in Interpol's history. The aim of this study was to resolve methods of the identification and results received. The viewpoint is mainly that of forensic odontology, but also includes other means of identification and results of the medico-legal examination performed in Finland. Of the 5395 victims in Thailand, approximately 2 400 were foreigners from 36 nations including 177 Finnish nationals. Additionally, a Finnish woman perished in Sri Lanka and a severely injured man after the evacuation in a hospital. The final numbers of missing persons and dead bodies registered in the Information Management Centre in Phuket,Thailand, were 3 574 ante-mortem (AM) and 3 681 post-mortem (PM) files. The number of identifications by December 2006 was 3 271 or 89% of the victims registered. Of Finnish victims, 172 have been identified in Thailand and 163 repatriated to Finland. One adult and four children are still missing. For AM data, a list of Finnish missing persons including 178 names was published on 30 December 2004. By February 2005 all useful dental AM data were available. Five persons on the list living in Finland lacked records. Based on the AM database, for the children under age 18 years (n=60) dental identification could be established for 12 (20%). The estimated number for adults (n=112) was 96 (86%). The final identification rate, based on PM examinations in Finland, was 14 (25%) for children (n= 56) and 98 (90%) for adults (n= 109). The number of Finnish victims identified by dental methods, 112 (68%), was high compared to all examined in Thailand (43%). DNA was applied for 26 Finnish children and for 6 adults, fingerprints for 24 and 7, respectively. In 12 cases two methods were applied. Every victim (n=165) underwent in Finland a medico-legal investigation including an autopsy with sampling specimens for DNA, the toxicological and histological investigation. Digital radiographs and computed tomography were taken of the whole body to verify autopsy findings and bring out changes caused by trauma, autolysis, and sampling for DNA in Thailand. Data for identification purposes were also noted. Submersion was the cause of death for 101 of 109 adults (92.7%), and trauma for 8 (7.3%). Injuries were 33 times contributing factors for submersion and 3 times for trauma-based death. Submersion was the cause of death for 51 (92.7%) children and trauma for 4 (7.3%). Injuries were in 3 cases contributing factors in submersion and once in trauma-based death. The success of the dental identification of Finnish victims is mainly based on careful registration of dental records, and on an education program from 1999 in forensic odontology.