Including root reinforcement variability in a probabilistic 3D stability model          下载免费PDF全文

Alessio Cislaghi  Enrico Antonio Chiaradia  Gian Battista Bischetti 《地球表面变化过程与地形》2017,42(12):1789-1806

Forests play a significant role in protecting people, settlements in mountainous terrains from hydrogeomorphic hazards, including shallow landslides. Although several studies have investigated the interactions between forests and slope instabilities, a full understanding of them has not yet been obtained. Additionally, models that incorporate forest stand properties into slope failure probability analyses have not been developed. In principle, physical‐based models, which are powerful tools for landslide hazard analyses, represent an appropriate approach to linking stand properties and slope stability. However, the reliability of these models depends on numerous parameters that describe highly complex geotechnical and hydrological processes (e.g. potential failure depth, saturation ratio, root reinforcement, etc.) that are difficult to measure and model. In particular, the spatial heterogeneity of root reinforcement remains a problem, and the use of physically based models from a forest management perspective has been limited. This paper presents a procedure for assessing slope stability in terms of the Factor of Safety that accounts for forest stand characteristics such as tree density, average diameter at breast height and minimum distance between trees. The procedure combines a three‐dimensional (3D) slope stability model with an evaluation of the variability of root reinforcement in terms of a probability distribution, according to forest characteristics. Monte Carlo simulation is used to account for the residual uncertainties in both stand characteristics and 3D stability model parameters. The proposed method was applied in a subalpine catchment in the Italian Alps, mainly covered by coniferous forest and characterized by steep slopes and high landslide risk. The results suggest that the procedure is highly reliable, according to landslide inventory maps [area under the ROC curve (AUC) is 0.82 and modified success rate (MSR) is 0.70]. Thus, it represents a promising tool for studying the role of root reinforcement in landslide hazard mapping and guiding forest management from a slope stability perspective. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

Simulating earthquake evacuation using human behavior models          下载免费PDF全文

Gian Paolo Cimellaro  Fabrizio Ozzello  Alessio Vallero  Stephen Mahin  Benshun Shao 《地震工程与结构动力学》2017,46(6):985-1002

In classical earthquake risk assessment, the human behavior is actually not taken into account in risk assessment. Agent‐based modeling is a simulation technique that has been applied recently in several fields, such as emergency evacuation. The paper is proposing a methodology that includes in agent‐based models the human behavior, considering the anxiety effects generated by the crowd and their influence on the evacuation delays. The proposed model is able to take into account the interdependency between the earthquake evacuation process, and the corresponding damage of structural and non‐structural components that is expressed in term of fragility curves. The software REPAST HPC has been used to implement the model, and as a case study, the earthquake evacuation by a mall located in Oakland has been used. The human behavior model has been calibrated through a survey using a miscellaneous sample from different countries. The model can be used to test future scenarios and help local authorities in situations where the human behavior plays a key role. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

Multidisciplinary Investigation of the Transform Fault Zones Doldrums and Vema during Cruise 45 of the R/V “Akademik Nikolaj Strakhov”     

Ivanova  E. V.  Skolotnev  S. G.  Borisov  D. G.  Demidov  A. N.  Bich  A. S.  Gippius  F. N.  Gryaznova  A. S.  Dobroliubova  K. O.  Zinger  T. F.  Korshunov  D. M.  Levchenko  O. V.  Mashura  V. V.  Muccini  F.  Nemchenko  N. V.  Peyve  A. A.  Pertsev  A. N.  Sani  K.  Sanfilippo  A.  Simagin  N. V.  Sokolov  S. Yu.  Ferrando  C.  Chamov  N. P.  Shakhovskoy  I. B.  Sholukhov  K. N. 《Oceanology》2020,60(3):424-426

Oceanology - Herein we provide information on the integrated geological, geophysical, sedimentological, paleoceanographic, hydrophysical and biological investigations in the Central Atlantic during...  相似文献   

Impacts of marine aquaculture at large spatial scales: evidences from N and P catchment loading and phytoplankton biomass   总被引：1，自引：0，他引：1  

Sarà G  Lo Martire M  Sanfilippo M  Pulicanò G  Cortese G  Mazzola A  Manganaro A  Pusceddu A 《Marine environmental research》2011,71(5):317-324

While several studies point at off-shore aquaculture as a possible source of impacts on the local marine environment, very few have analysed its effects at large scales such as at the bay, gulf or basin levels. Similar analyses are hampered by the multiple sources of disturbance that may concomitantly affect a given area. The present paper addresses these issues taking the Gulf of Castellammare (Southern Tyrrhenian Sea) as an example. Nitrogen (N) and phosphorous (P) loads were calculated for the period 1970-2007, and compared to chlorophyll-a concentration as measured inside and outside the Gulf over the same period. Results indicate that N and P catchment loading has constantly decreased because of improved environmental management. Nevertheless, nutrient concentration in the Gulf has steadily increased since the establishment of aquaculture facilities in 1999. Chlorophyll-a concentration followed this trend, showing a marked increase from 2001 onwards. In the same period, chlorophyll-a concentrations measured inside and outside the Gulf have significantly diverged. As all the other possible causes can be ruled out, aquaculture remains the sole explanation for the observed situation. This paper demonstrates for the first time ever that off-shore aquaculture may affect the marine ecosystem well beyond the local scale and provides an additional element of concern to be kept into consideration when allocating oceans' space for new fish-farming activities.  相似文献