The influence of intense rainfall on the activity of large-scale crystalline schist landslides in Shikoku Island, Japan

Many large landslides in the crystalline schist region of Shikoku Island, Japan, are susceptible to intense rainfall. Through the use of on-site monitoring systems, the activity of landslides and their meteorological triggers can be assessed. Continuous high-intensity rainfall was found to play a key role in provoking landslide movement. This paper investigates the influence of intense rainfall on the activity of crystalline schist landslides by examining rainfall and displacement of four typical landslides. By defining and calculating the effective rainfall and the relative landslide displacement, the relationship between intense rainfall and rainfall-induced landslide movement was analysed. Results indicate that the intense rainfall-induced landslide movement can be correlated with the effective rainfall. From these results, two rainfall thresholds were identified for the landslide risk management of Shikoku Island.     

蒙特卡罗模拟在区域地震滑坡灾害评价中应用

2004年10月23日,日本新泻中越地区发生史上最强地震之一,震级达到Mw6.6。这次地震诱发上千个规模大小不一、形式各样的滑坡,造成一定的灾害损失和人员伤亡。因此,为了有效地避免和减轻这方面的灾害,有必要有效地、科学地预测和评价地震诱发滑坡的空间发生规律。为此以一定的地区作为研究对象,提出了蒙特卡罗随机模拟和Newmark滑动体位移分析法在区域地震斜坡失稳概率分析中的应用。该法充分考虑到岩土参数和相关地震参数空间变异性,结合地理信息系统空间分析的优势,以网格模型为基础,分析该区斜坡滑动体位移分布规律,并以2cm为失稳临界值探讨网格斜坡破坏的概率。实例证明,所提出的模型有效地预测了滑坡发生的空间分布规律。     

The Second World Landslide Forum, Rome, 3�C9 October 2011: state of art at May 2011

The World Landslide Forum (WLF) is a triennial mainstream conference aimed at gathering scientists, stakeholders, policy makers and industry members dealing with the management of landslide risk. The First World Landslide Forum, organised by the International Consortium of Landslides, UNESCO, WMO, Food and Agriculture Organization, UNISDR, UNU, UNEP, IBRD, UNDP, ICSU, WFEO, KU and the Japan Landslide Society, was held in 2008 at the United Nations University, Tokyo. The 1st WLF adopted the 2008 Tokyo Declaration “Strengthening the International Programme on Landslides with UNISDR”. The Second World Landslide Forum has the objective to further develop the outcomes of the First Forum in Tokyo 2008 by providing a global cross-cutting information and cooperation platform for all types of organisations representing academia, United Nations organisations, governments, private enterprises and individuals that contribute to landslide research, practice, education and decision making and are willing to strengthen landslide and other related Earth system risk reduction strategies. The emphasis of this forum will be “Putting Science into Practice” with special attention given to actual implementation of technology and research in everyday applications and procedures with the direct involvement of researchers, engineers, private enterprises, stakeholders as well as policy and decision makers. The abstract submission and pre-registration of participants was quite successful with 649 received abstracts and more than 800 participants at May 2011. The full organisation of the event is now in progress taking into consideration the new figure and interest in scientific community and stakeholders.     

Formation process of two massive dams following rainfall-induced deep-seated rapid landslide failures in the Kii Peninsula of Japan

Extreme heavy rainfall due to Typhoon Talas on September 2–4, 2011 in the Kii Peninsula, Japan, triggered numerous floods and landslides. This study investigates the mechanism and the entire process of rainfall-induced deep-seated landslides forming two massive dams in the Kuridaira and Akatani valleys, respectively. The mechanism of the rapid deep-seated landslides is examined through a series of laboratory experiments on samples from sliding surfaces by using undrained high-stress dynamic-loading ring-shear apparatus. The test results indicate that the failure of samples is triggered by excess pore water pressure generation under a shear displacement from 2 to 7 mm with a pore pressure ratio ranging from 0.33 to 0.37. The rapid movement of landslides is mainly attributed to high mobility due to the liquefaction behavior of both sandstone-rich and shale samples. Geomorphic settings and landslide mobility are major contributing factors to the dam formation. Additionally, shear displacement control tests show that a certain amount of shear displacement between 2 and 7 mm along the sliding surfaces of the gravitationally deformed slopes might have led to the failures. Importantly, computer simulation with LS-RAPID software using input parameters obtained from physical experiments is employed to interpret the entire formation process of the abovementioned two landslide dams. The simulation results are examined in accordance with the observed on-site geomorphic features and recorded data to explain the possibility of sliding processes. The results further point out that local failures are initiated from the lower middle part of the landslide bodies where the geological boundary exists. This condition most probably influences the landslide initiation in the two case studies. This research is therefore helpful for hazard assessment of slopes that are susceptible to deep-seated landslides and other sequential processes in areas with geology and geomorphology similar to that of the Kii Peninsula.     

ICL strategic plan 2012–2021—To create a safer geo-environment

The International Consortium on Landslides (ICL) was founded on 21 January 2002, during the United Nations Educational, Scientific and Cultural Organization?CKyoto University Joint Symposium on Landslide Risk Mitigation and Protection of Cultural and Natural Heritage, as an activity of IGCP-425. In its first decade, ICL established the first scientific full-color journal Landslides, a new International Programme on Landslides, organized and held the First World Landslide Forum in 2008 and the Second World Landslide Forum in 2011, and recognized 15 World Centres of Excellence on Landslide Risk Reduction. A 10th anniversary conference was held on 17?C20 January at the facility in which ICL??s founding meeting had been held. This conference was jointly organized by ICL and ICL-supporting organizations. During the conference, the ICL Strategic Plan 2012?C2021: to create a safer geo-environment??was developed and adopted. This strategic plan accompanies this preface.