応用水文 = Applied hydrology

Exploring and identifying structure is even more important for multivariate data than univariate data, given the difficulties in graphically presenting multivariate data and the comparative lack of parametric models to represent it. Unfortunately, such exploration is also inherently more difficult.

Multivariate Density Estimation

IAEG Commission No. 1—Engineering Geological Maps—is developing a guide to hazard maps. Scientists from 17 countries have participated. This paper is one of a series that presents the results of that work. It provides a general review of GIS landslide mapping techniques and basic concepts of landslide mapping. Three groups of maps are considered: maps of spatial incidence of landslides, maps of spatial–temporal incidence and forecasting of landslides and maps of assessment of the consequences of landslides. With the current era of powerful microcomputers and widespread use of GIS packages, large numbers of papers on the subject are becoming available, frequently founded on different basic concepts. In order to achieve a better understanding and comparison, the concepts proposed by Varnes (Landslide hazard zonation: a review of principles and practice, 1984) and Fell (Some landslide risk zoning schemes in use in Eastern Australua and their application 1992; Landslide risk assessment and acceptable risk. Can Geotech J 31:261–272, 1994) are taken as references. It is hoped this will also add to the international usefulness of these maps as tools for landslide prevention and mitigation. Six hundred and sixty one papers and books related to the topic are included in the references, many of which are reviewed in the text.

Engineering geology maps: landslides and geographical information systems

Why Big Fierce Animals are Rare: An Ecologist's Perspective. By Paul Colinvaux. Pp.236. (Princeton University Press: New Brunswick, New Jersey, 1978.) $9.50.

How Nature works

Experimental characterization of shrinkage and desiccation cracking in thin clay layer

Meshfree modelling of one-dimensional contaminant migration

The analytical evaluation of the bearing capacity of the ring footing and cutting edge of the open caisson requires a definition of the size of failure zone in the soil, whereas the failure zone in soil depends on the type of soil and the configuration of the ring footing and cutting edge of the open caisson. In the study, the 1 g model tests are carried out to evaluate the failure zone in the sand beneath the ring footing and cutting edge of the circular open caisson. The radii ratio of the ring footing and cutting edge of the open caisson models are varied as ri/ro = 0.615, 0.737, and 0.783, and the tapered angle of cutting edge models is varied as β = 30° and 45°. The radius ratio is the ratio of internal radius to the external radius of the ring footing and cutting edge of the open caisson. The ring footing and caisson models are fabricated using Teflon tubes, and Indian standard sand is used as soil medium. The image-based deformation measurement technique is used to evaluate the failure zone in sand. The image analysis results are validated from the rigid displacement test.

Experimental Evaluation of Failure Zone in Sand Beneath the Ring Footing and Cutting Edge of Open Caisson Using Image Analysis

Delineation of the seismic area source zone is an important step in seismic hazard analysis which is carried out mainly on the basis of geographical, geological and/or seismotectonic characteristics of the region. Hence it requires knowledge or involvement of the experts from these fields, and yet the zonation suffers from subjectivity. This is especially true in the case of distributed seismicity where a correlation between geological features and earthquakes does not exist. One of the alternatives to the conventional method of area zoning in such cases is the zone-free approach. One of the zone-free approaches is the kernel technique of hazard estimation wherein the seismicity of a region, defined in terms of the Gutenberg–Richter (G–R) recurrence law, is replaced by a spatially smoothened activity rate probability density function. Chennai city lies in a low to moderate seismicity region and there are no major faults causing earthquakes in this region. The kernel method is used in estimating the probab...

Probabilistic seismic hazard analysis using kernel density estimation technique for Chennai, India

One of the forms of natural disasters given much attention by researchers all over the world during the International Decade for Natural Disaster Reduction (1990-2000) is the occurrence of landslides. Landslides take place in various regions of India, notably in the Himalayas and the Western Ghats, especially during monsoon. This paper describes some of the on-going studies related to modelling and risk evaluation of landslides at IIT Bombay, India. The studies described are: (i) rainfall induced landslide evaluation using DEM and GIS, (ii) fractal modelling of mass movement including critical failure surface determination using shortest path concept of GIS and (iii) evaluation of risk due to landslide. The unconventional methods used here demonstrate the usefulness of a GIS based technique in identifying potential slide regions in a long stretch of a hill slope and the corresponding risk, which could serve as supports for landslide hazard management.

G. R. Dodagoudar

Papers

Meshfree modelling of one-dimensional contaminant migration

Experimental Evaluation of Failure Zone in Sand Beneath the Ring Footing and Cutting Edge of Open Caisson Using Image Analysis

Probabilistic seismic hazard analysis using kernel density estimation technique for Chennai, India

Landslide modelling using remote sensing and GIS

Stability Analysis of Dyke Using Limit Equilibrium and Finite Element Methods