La nucleolectrica de Laguna Verde : ¿Convierte a México en zona de alto riesgo?

Cuestionamiento de la existencia de riesgo nuclear que presenta la planta nuclear Laguna Verde (LV) en México. Se expone la alta probabilidad de una accidente y por lo tanto, en estas circunstancia pordría pensarse que hay medidas eficaces contempladas para proteger la población, en caso de darse una emergencia nuclear, primero evacuando y después impidiendo la ingestiónd e radioisótopos

Liquefaction criteria based on statistical and probabilistic analyses

Probabilistic procedures for evaluating liquefaction resistance have the advantage of allowing an acceptable level of risk to be specified by the user. Liao and his colleagues used a logistic procedure to develop probabilistic CRR curves. The original Seed and Idriss magnitude scaling factors, however, we ussed to correct for magnitude. Youd and Noble (herein) use the logistic procedure to analyze liquefaction resistance with a magnitude added as an independent variable. New case history data and (N) were added to enlarge the case history data set. Primary conclusions from the study are: The probabilistic procedure allows direct incorporations of an appropriate probability, or risk factor in liquefaction hazard analyses.- The analyses by Liao and his collegegues indicate, for clean sands, that the standard criteria from the simplified procedure provides a probability of occurrence of about 20

for corrected blow counts (N) between 11 and 28. Below an (N) of 11 the original simplifiesd base curve is characterized by a probability of liquefaction smaller than 20

. Above an)N) of 28, the curves of Liao et al. indicate a probability of liquefaction greater than 20

. The curves in the upper par of the range, however, aare near the limit of liquefaction occurrences and are not well constrained by empirical data. - The analyses by Youd and Noble include magnitude as an independent variable eliminating the need for magnitude scaling factors in the analysis. The Youd and Nobel results are more conservative than those of Liao et al. for (N) lees than 20 and characteriza the simplified base curve bby probabilities ranging from 20

to 50

. (AU)

Probabilistic fault displacement analysis

A methodology to perform probabilistic fault displacement analysis (PFDA) for a given site on an active fault (or active faults) is presented.(AU)

Estimación del riesgo volcánico en términos de la distribución estadística de erupciones explosivas

El análisis de los patrones de ocurrencia de las erupciones volcánicas explosivas, puede mejorar nuestra comprensión de los procesos físicos que gobiernan a los fenómenos eruptivos. Desafortunadamente los intentos reportados en la literatura especializada de encontrar una distribución estadística de las erupciones no han coincidido en un resultado único. Sin embargo, cuando se clasifica a las erupciones por su tamaño o magnitud, se encuentra que, para los valores intermedios y altos de magnitud e intensidad, los patrones de ocurrencia de erupciones de un volcán pueden ser descritos por una distribución no estacionaria de poisson. Cuando se considera en forma conjunta la actividad de un numero grande de volcanes, la distribución tiene a ser estacionaria. Esto acarrea dos consecuencias fundamentales: En el caso de idividuales permite un análisis Bayesiano del nivel de riesgo presente, en base a la historia pasada, y en el caso global, en el que se toma en cuenta la información existente para todos los volcanes explosivos sub-aéreos a nivel mundial, permite la definición de una escala estadística de magnitudes. Con estos criterios, se analiza el estado de riesgo del volcán de Colima, considerado el más peligroso de México, y a nivel global se evalúa el pelígro asociado a una erupción paroxismal. (AU)

Probabilidad de presentación de ciclones tropicales en México

Con base en la información estadística de ciclones, se planteó un modelo que evalúa la probabilidad de ocurrencia de ciclones en el Golfo de México, Mar caribe y Oceáno Pacífico cerca de la República Mexicana. Se elaboró un mapa de méxico donde se señala la probabilidad anual de que pase un ciclón de determinada magnitud. ello puede servir para calcular en formaaproximada la probabilidad de que ocurran ciertos valores de marea de tormenta, viento oleaje y lluvia asociados a la intensidad del ciclón. (AU)

Long-term earthquake prediction in the North Pacific seismic zone based on the time and magnitude predictable model

Earthquake recurrence intervals for large and great shallow mainshocks in 12 seismogenic sources along the North Pacific seismic zone (Alaska-Aleutians-Kamchatka-Kuril Islands) have been estimated and used for the determination of the following relations: log Tf = 0.30 Mmin + 0.15 Mp-0.27 log Mo+ 5.24, Mf = 1.05 Mmim- 0.47 Mp + 0.60 log Mo -12.39, Where Tf is the interevent time, measured in years, Mmin the surface wave magnitude of the smallest mainshock considered, Mp the magnitude of the procceding mainshock Mf the magnitudes of the following mainshock Mo the moment rate in each source per year. The positive dependence of Tf on the Mp implies that the time-predictable model is valid for the area under examination, a very interesting property, since it contributes to the realistic progress toward the long-term prediction of earthquakes.

Probabilistic seismic hazard evaluation in underground mines

Stress concentrations produced by rock deformation due to extraction in underground mines induce seismicity thet can take the shape of violent and quite dangerous rockbursts. The hazard evaluation presented in this paper is based on a Bayesian probabilistic synthesis of information determined from mining situations during excavation, with previous and present data from microseismicity and seismoacustics. The method proposed in this study is an example of time-dependent on-line seismic hazard evaluation. All results presented were obtained retrospectiely for different underground coal mines in Poland and Czechoslovakia.(AU)

Multidisciplinary research carried out in the sample area of southern latium aimed at defining the seismotectonic model of the area

The main geological, geochemical, historical and geophysical researches carried out for many years by ENEA, in collaboration with researches of other organizations, aimed at the definition of a possible neotectonic and seismotectonic model of the area, are listed. The research are of primary importance for the study of seismic hazard and of late Quaternary climatic variations.(AU)

Maximum likelihood estimation of seismic hazard for Sweden

The maximum magnitude, the activity rate, and the Gutenberg-Richter b parameter as earthquake hazard parameters, have been evaluated for Sweden. The maximum likelihood method permits the combination of historical and instrumental data. The catalog used consists of 1100 earthquakes in the time interval 1375-1989. The extreme part of the catalog contains only the strongest historical earthquake, whereas the complete part is divides into several subcatalogs, each assumed complete above a specified threshold magnitude.(AU)

Seismic hazard analysis in Taiwan Region - Uncertainty analysis

The objetives of this paper are (1) to evaluate the seismic hazard in the taiwan Region, and (2) to obtain estimates on the effect on uncertainities of the hazard model. Uncertainty abalysis of model parameters in hazard analysis are concentrated on the analysis is dispersion of PGA and the probabilistic modeling of stationary and nonstationary Poisson model of occurrences. The estimation of b- value in the region is also presented in terms of an iso - acceleration map. The overall results are considered to be conservative since for most uncertainty analysis results the more conservative values are used (AU)

Methodology for earthquake zonation of continental regions - example for the Sydney region, Australia

The scope of earthqiuake disasters in terms of potential human loss and property damage is increasing because of the population increase and consequent expansion of infrastructure and critical facilities. Mitigation of the earthquake hazard is a major goal both for plate margins and continental regimes, through the United Nations' International Decade for Natural Disaster Reduction (IDNDR) (AU)

Where the Indian and Eurasian plates continue to collide

The article deals with the present day status of information regarding earthquakes in India. A brief mention is made of the Himalayan earthquakes and attention is drawn to very high seismicity including four great earthquakes exceeding magnitude 8 from 1867 to 1950. Seismic stations and strong motion arrays in operation are briefly commented upon. A mention is made of the existing earthquake resistant design of structures, building codes and insurance policies. A reference is made to a medium-term forecast, probabilistic seismic hazards estimates and scenarios developed if past major earthquakes were to repeat today. With India being the site of the largest and most sustained reservoir induced earthquakes at Koyna, a mention is also made of the worldwide problem of reservoir induced seismicity.(AU)