Earthquake Threat Research Articles

東日本大震災の初動報道に関する当事者分析 : キャスター自身による分析・調査と実践的考察

東日本大震災の初動報道に関する当事者分析 : キャスター自身による分析・調査と実践的考察

The Impact of Earthquake/Tsunami Threat on Land Prices in Padang, West Sumatera, Indonesia

Objective - In this study, the impact of earthquake/tsunami threat on land prices is measured using the Hedonic Price Method (HPM). The location of the research is in Padang, West Sumatra. The subject of study is land owners who purchased their land later than September 30, 2009. Methodology/Technique - The linear model and Double-log model with Ordinary Least Square (OLS) are used to estimate variable. Findings - The findings reveal that the Linear model have five variables with a significant effect. Those variables are: (1) Environmental quality, (2) Distance to the seafront, (3) Distance to educational facilities, (4) Availability of clean water and (5) Position of the land, whereas the double-log model also have 5 variables: (1) Distance to the seafront, (2) Distance to educational facilities, (3) Access to evacuation routes, (4) Availability of clean water and (5) Position of the land. Novelty - The possibility of earthquake and tsunami threat in the future has raised a new parameter associated with the environment in the city of Padang, namely land distance towards the seafront. The findings of the study contribute the understanding in land pricing. Type of Paper: Empirical Keywords: Earthquake/Tsunami; Environmental Quality; Land Prices; Padang. JEL Classification: Q24, Q54.

NEHRP Turns 40

This year, the National Earthquake Hazards Reduction Program (NEHRP) turns 40, four decades since the Earthquake Hazards Reduction Act of 1977 was enacted establishing the Program, spurring numerous federal, state, and community actions to reduce earthquake losses in the U.S.A. and its territories and setting a standard for earthquake loss‐reduction projects internationally. Four agencies are partners in NEHRP: the Federal Emergency Management Agency (FEMA), the National Institute of Standards and Technology (NIST, the lead agency), the National Science Foundation (NSF), and the U.S. Geological Survey (USGS). Remarkably few major earthquakes have occurred since 1977, in terms of economic impact, so the earthquake threat has faded from the memories of most Americans, even as geologists and seismologists have identified and quantified a number of fault systems that pose risks of national economic scale. The genesis of NEHRP has been well covered in previous summaries by Wallace (1996) and Hamilton (2003), each of whom described the earthquakes, the people, and the reports that led to the passage of the 1977 Act. The 1964 Alaska and 1971 San Fernando earthquakes were, of course, seminal events. Several expert panels weighed in, there was great enthusiasm for earthquake prediction, and even the ephemeral Palmdale Bulge contributed. There is no need to repeat those good stories here; instead, I will review what has been accomplished since the Act was passed and what key objectives are yet to be realized. In this space, it will not be possible to cover this topic comprehensively, so indulge me while I survey just a few highlights. First, remarkably few major U.S. earthquakes have occurred since 1977, at least in terms of economic impact. In fact, only three have caused losses greater than $1 billion: 1989 Loma Prieta, $10.7 billion; 1994 Northridge, $64.0 billion; and 2001 Nisqually, $2.7 billion (Wilkerson, …

Tsunami hazard in Central America: history and future

Abstract Central America is a small and culturally homogeneous region that, since the 1990s, has experienced economic and political integration of its six countries, which share the same threats of volcanic eruptions, disastrous earthquakes and tsunamis. The Pacific coastline of 1700 km is common for Guatemala, El Salvador, Honduras, Nicaragua, Costa Rica and Panama, and the Pacific subduction zone has the potential for creating huge tsunamis that threaten this coast. In addition to the natural hazard, the growing tourist industry is expanding its infrastructure along the Pacific beaches, which again enhances the exposure and tsunami risk. Even though the 1992 tsunami disaster in Nicaragua did not severely hit the tourist beaches, it raised the risk awareness, and special attention is now given to ‘slow’ earthquakes that may be modest in shaking while still having a large tsunami potential. The tsunami hazard mapping is well advanced in Nicaragua, Costa Rica and El Salvador, and initiatives are ongoing to improve the mapping in all countries. National systems for early warning were established in Nicaragua and El Salvador, while the other four countries rely on rapid information from the Pacific Tsunami Warning Center. Mitigation measures and information campaigns are presently conducted on a national basis in all countries, but a regional centre for early tsunami warning and coordinated information campaigns (CATAC) is expected to become operational in the near future.

Kinematics of the active West Andean fold-and-thrust belt (central Chile): Structure and long-term shortening rate

West-verging thrusts, synthetic with the Nazca - South America subduction interface, have been recently discovered at the western front of the Andes. At ~33°30’S, the active San Ramon fault stands as the most frontal of these west-verging structures, and represents a major earthquake threat for Santiago, capital city of Chile. Here we elaborate a detailed 3D structural map and a precise cross-section of the West Andean fold-and-thrust belt based on field observations, satellite imagery and previous structural data, together with digital topography. We then reconstruct the evolution of this frontal belt using a trishear kinematic approach. Our reconstruction implies westward propagation of deformation with a total shortening of 9-15 km accumulated over the last 25 Myr. An overall long-term shortening rate of 0.1-0.5 mm/yr is deduced. The maximum value of this shortening rate compares well with the rate that may be inferred from recent trench data across the San Ramon fault and the slip associated with the two past Mw > 7 earthquakes. This suggests that the San Ramon fault is most probably the only presently active fault of the West Andean fold-and-thrust-belt and that most - if not all - the deformation is to be released seismically.

Neotectonics and seismicity of Erzurum pull-apart basin, East Turkey

The study area is the Erzurum pull-apart basin located in the East Anatolian Tectonic Block (EATB), which is under the control of a strike-slip neotectonic regime since the beginning of Quaternary. The Quaternary Erzurum pull-apart basin is an about 1-30 km wide, 90 km long and actively growing strike-slip depression. It is bounded by the Erzurum-Dumlu sinistral strike-slip fault zone to the east-southeast, by the Askale sinistral strike-slip fault zone to the north-northwest, and by the Baskoy-Kandilli reverse fault zone and the N-S-trending Ilica oblique-slip normal fault set to the west. The Erzurum pull-apart basin was evolved by the deformation and subdivision of an E-W-trending older intermontane basin. The new basin has a 0.5 km thick, flat-lying (undeformed) and uconsolidated fill, which overlies, with an angular unconformitry, the deformed (folded and faulted) basement rocks of pre-Quaternary age. Basin fill consists of coarser-grained marginal facies (fault terrace, fan, fan-apron and superimposed fan deposits) and finer-grained depocentral facies represented by flood plain to organic material-rich marsh deposits. All gradations are seen among these lithofacies.The seismicity of the Erzurum pull-apart basin is quite high. The magnitude of the peak earthquake to be sourced from the active faults (e.g., the Erzurum fault) is about Mw = 7.0. This was proved by both the historical and recent earthquakes. Numerous settlements in the size of a large city (e.g., Erzurum), county, town and small villages with a total population of over 766,000 are located in and along the active fault-bounded margins of the Erzurum pull-apart basin. They are under the threat of destructive earthquakes to be sourced from the margin-boundary faults. Therefore, based on both the active fault parameters and the water-saturated basin fill, a large-scale earthquake hazard map has to be prepared. This map has to be used in both the earthquake hazard to risk analyses and the redesign of city planning and all type of constructions in Erzurum and other settlements in this region.

Dynamic properties of Byblos municipality building with soil-structure interaction using geophysical methods

Byblos city is located on the coast north of Beirut, Lebanon, and is one of the oldest continuously-inhabited cities in the world. It is exposed to a moderate-up-to-high level of seismic activity, given its proximity to several major faults such as the Yammouneh and the Mount Lebanon Thrust, among others. To mitigate the risk encountered by Byblos buildings facing earthquake threat, a preliminary study of the dynamic properties of the structures is proposed in this paper. The recently-constructed Byblos Municipality building was chosen as a prototype for this study, given its important role as a vital structure for centralizing the emergency response, in the event of a disaster.The approach consists of using the horizontal to vertical ratio method, HVNR. By analysing the ambient noise recordings, one can determine the structural frequency, damping, and other stiffness characteristics, and identify the natural soil frequency. In order to investigate the soil structure interaction and specifically possible resonance occurrence during earthquakes, the values obtained are compared and analysed. In addition to classical geotechnical tests to reveal the type and properties of the considered in-situ soil, the multichannel analysis of surface waves, MASW, is used to investigate the stiffness of the subsurface conditions and determine the shear wave velocities of the layers. In parallel, the Finite Element Model of the structure is analysed and the result of the fundamental resonance frequencies is compared to the HVNR data, and to the computed values using conventional formulae recommended by classical building codes. Results and comparisons of experimental and numerical investigations are presented for the structure and analysed for further resonance analysis.

Factors and Processes Affecting Levee System Vulnerability

doi: https://doi.org/10.15447/sfews.2016v14iss4art3 We appraised factors and processes related to human activities and high water, subsidence, and seismicity. Farming and drainage of peat soils caused subsidence, which contributed to levee internal failures. Subsidence rates decreased with time, but still contributed to levee instability. Modeling changes in seepage and static slope instability suggests an increased probability of failure with decreasing peat thickness. Additional data is needed to assess the spatial and temporal effects of subsidence from peat thinning and deformation. Large-scale, state investment in levee upgrades (> $700 million since the mid-1970s) has increased conformance with applicable standards; however, accounts conflict about corresponding reductions in the number of failures. Modeling and history suggest that projected increases in high-flow frequency associated with climate change will increase the rate of levee failures. Quantifying this increased threat requires further research. A reappraisal of seismic threats resulted in updated ground motion estimates for multiple faults and earthquake-occurrence frequencies. Estimated ground motions are large enough to induce failure. The immediate seismic threat, liquefaction, is the sudden loss of strength from an increase in the pressure of the pore fluid and the corresponding loss of inter-particle contact forces. However, levees damaged during an earthquake that do not immediately fail may eventually breach. Key sources of uncertainty include occurrence frequencies and magnitudes, localized ground motions, and data for liquefaction potential. Estimates of the consequences of future levee failure range up to multiple billions of dollars. Analysis of future risks will benefit from improved description of levee upgrades and strength as well as consideration of subsidence, the effects of climate change, and earthquake threats. Levee habitat ecosystem benefits in this highly altered system are few. Better recognition and coordination is needed among the creation of high-value habitat, levee needs, and costs and benefits of levee improvements and breaches.

MODEL SPASIAL KERENTANAN DIKAWASAN PESISIR SELATAN TELUK BETUNG KOTA BANDAR LAMPUNG TERHADAP BENCANA TSUNAMI

ABSTRACT
 Bandar Lampung is an area in Indonesia which has a high level of Tsunami threat. It is due to the position of Bandar Lampung which is located relatively near the meeting point of Indo-Australian plate dan the Eurasian plate; both are plates are relatively active. Other causes are earthquake threat and the existence of Krakatoa which is potential to generate earthquakes which are followed by a Tsunami. The data analysis showed that the potential Tsunami hazard in the coastal city of Bandar Lampung is the predicted distance run up the marinade tsunami that reached a height of 20 meters above sea level. Potential hazards include four districts, i.e. Bumi Waras District, Panjang District, South Teluk Betung District, and East Teluk Betung District. The research method is Cell-Based modeling, the one using the tool model builder in Arc GIS with 1 meter raster grid analysis, which can show and explain in detail the attributes that exist in the region. From Quick Bird image that has of 0.6 meter resolution, the existing condition of the land use can be clearly seen. The results of the analysis showed the vulnerability of Tsunami in the city of Bandar Lampung. The results showed that Bumi Waras District has the highest vulnerability level at Bumi Waras Subdistrict with an area of 85.62 Ha. Panjang District has the highest level of vulnerability at Pidada Subdistrict with an area of 30.16 ha. South Teluk Betung District has the highest level of vulnerability at Pesawahan Subdistrict with an area of 0,02 Ha. East Teluk Betung District has the highest level of vulnerability at Kota Karang Subdistrict with an area of 32.11 Ha. Keywords: Tsunami disaster, Vulnerability and cell-based modeling

Ecological Management and the Cosmogenic Mechanism of Earthquakes

Critical issue of ecological risk management in urban areas is to predict the evolution of the dangerous natural processes intensity. The special situation in the realization of these risks take the earthquake threat and the stresses emergency fluctuations in the geological environment of the buildings and structures bases. This article is devoted to one of the main problems of earthquake engineering - verification of the dominant mechanisms and causality of the earthquakes intensity dangerous evolution. In it discusses the comparative analysis results of the Earth gravitational interaction energy variations amplitudes with the Sun, with the Moon and the solar system planets. Also presented the comparative evaluations results of the Earth geospheres gravitational perturbations amplitudes with the Earth solar radiation energy with the energy of its own heat of the Earth. It is shown that the energy of his own heat and Sun exposure of the Earth much less energy to gravitational perturbations in the near-earth space. In the article presents the spectral analysis results of earthquakes global daily energy on the Earth before and after the Shoemaker-Levy comet explosion on Jupiter. It is shown that the seismic events number on Earth with magnitude greater than 2.5 on the Richter scale after the comet explosion increased in 10 times. In the earthquakes global daily energy spectrum shows the spectral manifestations of solar system planets gravitational resonances. In given article the researches results of natural disasters cosmogenic sources power allow us to argue that ecological risk effective management is impossible without the evolution forecast of the cosmogenic effects intensity on natural processes for sustainable urban development.

Sustainable Non-destructive Technique Ambient Vibrations for Ground Assessments

Sustainable approach, cost-effective, precise and reliable outcomes become a great challenge in monitoring or re-evaluating the existing site-structure especially with minimum engineering database. Simple, fast, cheap, non-destructive, minimum handling operator and reliable findings of ambient vibration testing (AVT) and Horizontal to Vertical Spectral Ratio (HVSR) method has proven successful in site dynamic characteristics assessments of SK Sri Molek situated in Batu Pahat district, Johor, Malaysia. Although many expectations believed the survival of existing low-rise building is higher under earthquake threat, but moderate resonance effect was classified at similar study area from previous investigation. Determination of site fundamental frequency, Fo may assist further evaluation in seismic hazard assessments, ground condition monitoring as well as local soil characterization. The Fo were obtained from 2.05 to 4.07Hz from the microzonation map produced with good verification presented between AVT outputs against two bore log records, for ground classification and sediment thickness predictions of sedimentary covers.

New insights on the seismogenic potential of the Eastern Betic Shear Zone (SE Iberia): Quaternary activity and paleoseismicity of the SW segment of the Carrascoy Fault Zone

AbstractThe Carrascoy Fault (CAF) is one of the main active faults that form part of the Eastern Betic Shear Zone, a 450 km fault system that accommodates most of the convergence between the Eurasian (Iberia) and Nubian plates in the Betic Cordillera, south Spain. Although the CAF represents a major earthquake threat to the nearby City of Murcia, studies on its Quaternary tectonics and seismogenic potential are scarce to date. We present evidence that supports the division of the CAF into two overlapping segments with contrasting tectonic structure, Quaternary activity, and landform control: a SW segment, characterized by a broad fold‐and‐thrust zone similar to the forebergs defined in the Gobi‐Altai region, and a NE segment, characterized by a sharp mountain front controlled by strike‐slip tectonics. We attribute the differentiation into these two segments to the stresses associated with topography, which in turn is a consequence of the shortening component, at the middle Pleistocene, after circa 217.4 ka. For the SW segment we infer the occurrence of 9 to 11, Mw 6.7 paleoearthquakes in the last 30.2 kyr, and a slip rate of 0.37 ± 0.08 m/kyr. We date the occurrence of the last surface rupture event after 2750 B.P., and we estimate an average recurrence period of major events of 3.3 ± 0.7 kyr.

WHEN THE DISASTER TREATMENT IN THE HEAD OF EYES: THE EFFORTS OF MITIGATION POLICY AND REDUCTION OF THE DISASTER RISK IN PADANG CITY

INTRODUCTION:Indonesia is situated on the three major straights of different world those are Eurasian tectonic straight, Iindo-Australian tectonic, and pasific straight affected Indonesia as a territory of troubled natural disaster especially earthquake, tsunamy and volcanic erruption (Sutikno in Napsiah, 2015:6). In connected with them that one of such situated city is Padang, West Sumatra. The earthquake happened in September 30, 2009 at 7.6 richter scale quaked West Sumatra Province. The greatest demage affected by earthquake was in 13 of 19 regencies/cities and stroke victims more than 1.100 people. The affected region of the most serious demage were Padang City, Pariaman, and Padang Pariaman Regency. The demage and disavdvantage in West Sumatra was approximately 21.6 quintillions or equivalently US$ 2.3 billions (Danhas 2011). Accordingly, the government of Padang City began paying attention to the earthquake disaster probabilities occuring in the next time because of regional condition at the troubled disaster.Besides, the experts research explained that Padang City and West Sumatra generally have high risk towards threat of earthquake with 8,9 richter scale. The potency is at the matching Euroasian straight and Indo-Australia, exactly in Mentawi archipelago. Strong assesment, the earthquake will result in great enough tsunamy wave that can destroy Padang City, such as tsunamy happened in Nangro Aceh Darussalam in the last 2004. Meanwhile, an expert of the earthquake of Indonesian Institute of Science (IIS) Danny Hilman thought that the great threating eaerthquake in the west Sumatra is increasingly nea.. This matter concerning with ongoing the great earthquake potency that isn't free from Mentawai segment. This segment stored the earthquake potency with 30 times over energy greater compared with earthquake in Padang last years. The great earthquake in (subduksi zone) Mentawai is always again and again goes along yearly cycle. The research result showed that the period of great earthquakes in that region ended in 1797 and 1833. While the 2007 earthquake in Mentawai region only lost three quarter of energy amount of accumulated tectonic pressure. The earthquake predicted resulting in tsunamy wave that swept the area in the West Sumatra beach at 5 kilometers circle from the beach edge. Padang is one of the threated city struck by tsunamy impact (vivanews.co.id, 2015).Accordingly, to avoid the worst probability that is going tobe caused by disaster so the thing todo for Padang City Government is to implement the policy of managing disaster based disaster mitigation, where mitigation (the efforts of reducing disaster impact). Mitigational action can be in specific programming type. This is tobe embodied in order that when the disaster occurs, this program can reduce the people victims and demages. There are two approches to do for Padang City in such mitigational policy, Structural Mitigation (building chekdam, river embankment, barrage, shelter, EWS, map, ect.) and Non Structural Mitigation (making regulation, lay -out, training, socialization (including spiritual mitigation). (BPBDPK Kota Padang, 2015).DISASTER MANAGEMENT:According to UNISDR (2009) that the definition of disaster is trouble towards people or community that caused occuring disadvantage and impacting spirit passing away, economy, and environment broadly, that excesses the impacted people abilities to face it by using their own resources.In many disasterous occuranes, the role that government does in terms of public policy and public administration to manage disaster is very important and great. There are various important paradigm changes tobe noticed in reducing disasterous risk (Pujiono, 2007).1. From emergency respond tobe disaster management : disaster management can not focus only on emergency management anymore (emergency respond) when the disaster has occured, except more to reducing the overall disasterous risk of the risk observation, prevention, mitigation, readiness, respond, rehabilitational restoration and reconstruction. …

Adaptación a la variabilidad climática entre los caficultores de las cuencas de los ríos Porce y Chinchiná, Colombia

This article seeks to explain the practices used by small farmers to cope with climate variability and extreme weather events in the basins of the Chinchiná and Porce rivers located on the central Andes in Colombia. The information wasglacie collected through interviews, observations on farms and workshops with farmers. Additionally historical averages on temperature, precipitation and sunshine were compared with those values recorded in 2010 during the transition between El Niño an La Niña events. During the first quarter of 2010 the average temperature in Chinchiná increased by 1.4 C° and the solar brightness by 14%, while the precipitation experienced a 46% reduction. In contrast, during the second half of the year there was a decrease of 0.8 C° in temperature, a 31% reduction in solar brightness and an increase in precipitation of 62%. The coffee production in the years 2011 and 2012 was the lowest in the country in the last 35 years despite the cultivated area increased. These changes affected the coffee plantations and substantially decreased grain coffe production. Coffee production in the years 2011 and 2012 was the lowest in the country in the last 35 years despite the cultivated area increase. These fall in coffee production was also a result of the renewal with rust resistant varieties, which at that time had not yet begun to produce. Most of the farmers have 5 hectares or less and are union members in the National Federation of Coffee Growers of Colombia (fncc), which provides multiple services to them including an extension service with spread of the findings of field investigations carried out by the National Coffee Research Center (cenicafe). These study results indicates some strategies used by peasants to minimize the effects of climate variability: the shade management in coffee plantations, especially with banana (Musa sp.) and guamo (Inga sp); their renewal with the rust resistant variety named Castillo; the association of crops, particularly coffee, maize and bean; the use of mulches, organic fertilizers and mycorrhizae; a proper fertilization; the cultivation of two-axis coffee plants; the staggered planting of coffee in different plots and the reforestation of hillsides and births water, especially with (Guadua angustifolia), are strategies used to minimize the effects of climate variability. However these strategies are more frequent in Porce than in Chinchiná where sun coffee plantations and intensive agriculture are predominants. The article indicates that adaptation to climate variability is not achieved only by technological measures if do not decrease the sources of vulnerability of the rural population. The farmers are more exposed to the effects of weather because of their poverty, as a result of building on steep slopes, by cause of the volatility in the international price of coffee, by virtue of the exchange rate, due to the lack of a culture of crop insurance and for the lack of generational renewal in agriculture. Additionally peasants in Chinchiná faced threats of earthquakes, eruption of Nevado del Ruiz volcano, susceptibility of volcanic soils to mass removals and glacier melting, an increasingly process accelerated by climate change. This paper also highlights the social, economic and political adaptation strategies to climate variability. We found that the resilience of rural households increases when resorting to agrotourism, integration of family labor, associations, political mobilization for claiming benefits, casual wage labor on other farms, integration to fair markets coffee and coffee certifications that increase the price of This work also highlights the social, economic and political adaptation strategies to climate variability. We found that the resilience of rural households increases when resorting to the agrotourism, integration of family labor, the union associations, political mobilization for claiming benefits, the casual wage labor on other farms, the integration to fair markets of coffee and coffee certifications that increase the price of grain of coffee grain. Not all spontaneous adaptation measures are positive, it is necessary to evaluate the experience of many coffee farms of medium length that were converted to livestock, rural tourism and citrus growing. Since climate change and climate variability has increased the frequency and intensity of extreme weather events, this work also helps to identify vulnerabilities and adaptation of rural populations to climate change and extreme events.

Citizens at risk from earthquake hazard in Dhaka city: Scaling risk factors from household to city region level

Dhaka city is under the looming threat of cataclysmic earthquake. However, the factors from which the citizens are at risk may not the same for its all parts. Dividing the city into three geographical scales: Old (Shankhari Bazaar), Developed (Segunbaghicha) and Newly Developing (Uttara 3rd Phase) areas, this research explores the risk factors of earthquake hazard from household to city-region level. Based on FGD at community level, in-depth interview of experts and policymakers, observation and secondary sources of data the study finds citizens of Old Dhaka are at high risk because of the obsolete and dilapidated building structures they live in whereas unauthorized high rise buildings is a massive threat for the dwellers living in developed Dhaka. The results of this research highlight that fact that enormous filling of low-lying lands enhances high earthquake risk and may cause severe liquefaction effects to the residents of newly developing areas of Dhaka. The comprehensive outcomes of this study are emphasized on raising the on-going public awareness programs, following the building codes strictly and implementing the disaster risk reduction approach into land use planning which can possibly reduce earthquake risk in Dhaka city.

Operational Earthquake Forecasting Can Enhance Earthquake Preparedness

We cannot yet predict large earthquakes in the short term with much reliability and skill, but the strong clustering exhibited in seismic sequences tells us that earthquake probabilities are not constant in time; they generally rise and fall over periods of days to years in correlation with nearby seismic activity. Operational earthquake forecasting (OEF) is the dissemination of authoritative information about these time‐dependent probabilities to help communities prepare for potentially destructive earthquakes. The goal of OEF is to inform the decisions that people and organizations must continually make to mitigate seismic risk and prepare for potentially destructive earthquakes on time scales from days to decades. To fulfill this role, OEF must provide a complete description of the seismic hazard—ground‐motion exceedance probabilities as well as short‐term rupture probabilities—in concert with the long‐term forecasts of probabilistic seismic‐hazard analysis (PSHA). > Operational earthquake forecasting is the dissemination of authoritative information about time‐dependent probabilities to help communities prepare for potentially destructive earthquakes. The status of OEF and guidelines for its deployment have been described in a comprehensive report by the International Commission on Earthquake Forecasting for Civil Protection (ICEF), which was convened by the Italian government following the L’Aquila earthquake disaster (Jordan et al. , 2011). The ICEF conceived of OEF not as a stand‐alone activity, but as one component of a larger system for guiding mitigation actions based on scientific information about the earthquake threat (Fig. 1). The proper role of OEF is to inform, but not prescribe, the response by end users to changing seismic hazards. The front end of an OEF system should be an interface for continually providing forecasting information that is timely, authoritative, and properly conditioned to serve multiple end users, including the general public. Figure 1. Schematic diagram of an operational earthquake forecasting system that provides probabilistic forecasting information (left side) through …

The Prediction Problems of Earthquake System Science

Editor’s note: The following is the text of the SSA Presidential Address presented at the Annual Luncheon of the Seismological Society of America (SSA) Annual Meeting on 30 April 2014. The Seismological Society of America (SSA) has always been dedicated to understanding and reducing the earthquake threat. The Society was founded in 1906 “for the acquisition and diffusion of knowledge concerning earthquakes and allied phenomena.” According to our new strategic plan, approved by the Board in 2012, the core purpose of SSA is to “advance seismology and the understanding of earthquakes for the benefit of society.” This plan lays out the vision for SSA to be “the primary forum for the assembly, exchange, and dissemination of scientific knowledge essential for an earthquake‐aware and safer world.” In the past twenty years or so, the study of earthquakes has become a true system science, offering new pathways for the advancement of seismology. Today I would like to explore what the rise of earthquake system science might imply for the future of our field and for SSA’s mission in earthquake research. System science seeks to explain phenomena that emerge from nature at the system scale, such as global climate change or earthquake activity in California or Alaska. The “system” is not a physical reality, but a hypothetical representation of nature, typically a numerical model that replicates an emergent behavior and predicts its future course. The choice of target behavior determines the system model, as can be illustrated by two representations of earthquake activity in California. One is UCERF3, the latest uniform California earthquake rupture forecast of the Working Group on California Earthquake Probabilities, which represents future earthquake activity in terms of time‐dependent fault‐rupture probabilities. Another is the Southern California Earthquake Center (SCEC)’s CyberShake ground‐motion model, which uses simulations to represent the probability of …

Spontaneous Activation of Schemata under Stress Getting control over earthquake threat

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Hazard and seismic reinforcement analysis for typical large dams following the Wenchuan earthquake

The primary aim of this research is to analyze the hazards and seismic performance of reservoirs and typical large dams based on a field investigation following the Wenchuan 8.0 earthquake. The current seismic performance standards being achieved are discussed and further suggestions are given for super high dams. Based on field investigations, statistics are also given on damaged small reservoirs and damage severities, due to the many various types of earthquake threat. It is of interest to note that the major structures of the medium-sized hydropower stations on the Minjiang river did withstand the Wenchuan earthquake, despite earthquake intensity exceeding engineering design expectations. All the dams remained overall stable. The Shapai roller-compacted concrete (RCC) arch dam and the Zipingpu concrete-faced rockfill (CFR) dam suffered damage. The main earthquake-induced hazards to the dam structures and to both abutments are detailed. Case study analyses of the hazards and reinforcement provision revealed that: 1) The Wenchuan earthquake proved very dangerous for small reservoirs, with destroyed reservoirs widely distributed. The risk of failure of small dams can be classified into three levels based on field investigation. 2) The damage to and behavior of the large dams in the area affected by the earthquake prove that the Chinese codes relating to the seismic design of large dams are appropriate. 3) Appropriate reinforcement can increase the overall stiffness of abutments, riverbed foundation and the adjacent slopes, further improving the seismic performance of dams. 4) The design and management of emergency responses, to cope with extreme conditions, should be improved, and a unified response platform, covering all hydropower engineering projects in each valley should be established. The effects to be expected and the seismic design measures to be taken still pose great challenges for engineers in respect of large dams.

The Ghost Forests of Cascadia: How Valuing Geological Inquiry Puts Practice Into Place

ABSTRACTInterpreting the hazards and appreciating the privileges of living in a particular place draw upon insights from multiple disciplines. Seemingly self-evident, this perspective stands as a counterpoint to the depiction of scientific practice as unified and independent of discipline in standards for the education of all Americans. Inquiry adapts in distinctive ways to different kinds of problems. By deciphering the distribution and timing of the demise of cedar trees—ghost forests—U.S. Geological Survey geologist Brian Atwater uncovered the threat of great subduction zone earthquakes in Cascadia. In research that interprets place, diverse inquiries cohere and bind local citizens to an appreciation of their landscape. Practices characteristic of geological inquiry, organized to interpret place, emphasize temporally and geographically restricted solutions, not universal knowledge. The importance of such practices casts doubt on the merits of scientific unity promoted by standards-driven reform.