Application of association rules to determine building typological classes for seismic damage predictions at regional scale. The case study of Basel

Assessing seismic vulnerability at large scales requires accurate attribution of individual buildings to more general typological classes that are representative of the seismic behavior of the buildings sharing same attributes. One-by-one evaluation of all buildings is a time-and-money demanding process. Detailed individual evaluations are only suitable for strategic buildings, such as hospitals and other buildings with a central role in the emergency post-earthquake phase. For other buildings simplified approaches are needed. The definition of a taxonomy that contains the most widespread typological classes as well as performing the attribution of the appropriate class to each building are central issues for reliable seismic assessment at large scales. A fast, yet accurate, survey process is needed to attribute a correct class to each building composing the urban system. Even surveying buildings with the goal to determine classes is not as time demanding as detailed evaluations of each building, this process still requires large amounts of time and qualified personnel. However, nowadays several databases are available and provide useful information. In this paper, attributes that are available in such public databases are used to perform class attribution at large scales based on previous data-mining on a small subset of an entire city. The association-rule learning (ARL) is used to find links between building attributes and typological classes. Accuracy of wide spreading these links learned on <250 buildings of a specific district is evaluated in terms of class attribution and seismic vulnerability prediction. By considering only three attributes available on public databases (i.e., period of construction, number of floors, and shape of the roof) the time needed to provide seismic vulnerability scenarios at city scale is significantly reduced, while accuracy is reduced by <5%

Extension of Gutenberg-Richter Distribution to Mw -1.3, No Lower Limit in Sight

With twelve years of seismic data from TauTona Gold Mine, South Africa, we show that mining-induced earthquakes follow the Gutenberg-Richter relation with no scale break down to the completeness level of the catalog, at moment magnitude MW −1.3. Events recorded during relatively quiet hours in 2006 indicate that catalog detection limitations, not earthquake source physics, controlled the previously reported minimum magnitude in this mine. Within the Natural Earthquake Laboratory in South African Mines (NELSAM) experiment\u27s dense seismic array, earthquakes that exhibit shear failure at magnitudes as small as MW −3.9 are observed, but we find no evidence that MW −3.9 represents the minimum magnitude. In contrast to previous work, our results imply small nucleation zones and that earthquake processes in the mine can readily be scaled to those in either laboratory experiments or natural faults

Use of the lost seismic infor-mation about upper part of geological structure for the not prospecting purposes

Показаны результаты переобработки потерянной в процессе поисков углеводородов сейсмической информации для картирования скоростной характеристики (скорости продольных волн) верхней части геологического разреза для сокращения дорогостоящих инженерно- поисковых работ для промышленного и гражданского строительства и успешного развития точного земледелия на территории нефтегазовых регионов.Показано результати переобробки втраченої в процесі пошуків вуглеводнів сейсмічної інформації для картування швидкісної характеристики (швидкості поздовжніх хвиль) верхньої частини геологічного розрізу для скорочення дорогих інженерно-пошукових робіт для промислового та цивільного будівництва та успішного розвитку точного землеробства на території нафтогазових регіонів.The results of reprocessing of the lost (in hydrocarbon prospecting process) seismic information for the mapping of velocity characteristic (velocity of longitudinal waves) of the upper part of geological structure for reduction of expensive engineering-prospecting works for industrial and civil construction and for successful development of precise agriculture on the territory of oil and gas regions is shown

Assessment of static and dynamic stresses horse-shoe tunnel with connecting gallery using finite element method: (as a case study)

This paper illustrates the use of MIDAS GTS NX to investigate the tunnel’s simulation in order to highlight the effect of static and dynamic load on the behaviour of tunnel to compare this response expressed in terms of displacement and stresses acting on the tunnel and ground. Main tunnel is located in the ground having uniform property throughout its extent, connecting gallery is located perpendicular to the main tunnel, the shotcrete and rock bolts for each tunnel will be installed

Management of post-mining large-scale ground failures : blast swarms field experiment for calibration of permanent microseismic early-warning systems

International audienceIn France, decades of coal and iron-ore mining have left extensive underground cavities beneath or in the vicinity of urban areas. This poses an environmental challenge for society. To ensure post-mining risk management and public safety, wherever remediation is not possible, numerous real-time microseismic monitoring systems are being installed. The objective is to detect remote rock mass fracturing processes, precursory events and acceleration phases for appropriate and timely action. Although no consistent collapse has occurred in any of the monitored areas yet, single 3-D probes record many microseismic events of very low amplitude which create difficulties in the quantitative data analysis. The development of specific quantitative processing has therefore become a major issue in our research work. For that purpose, a field experiment was carried out on six of the instrumented sites. It consisted of sequences of small blasts in mine pillars which were accurately controlled in terms of the location, orientation and energy of the explosive source. The data analysis was used to calibrate parameters (velocity model, 3-D sensor orientation, etc.) for reliable 3-D localization and to develop an empirical law to estimate the source energy from the sensor energy. This work now enables us to analyze real microseismic events with a considerably better level of accuracy and to obtain enough information and confidence to discuss these data in terms of site stability