we're looking at coarse-grained sedimentary rocks of the basin margin. you can see that the clasts are large and very angular and that the rocks are very poorly sorted-- that is, it's a mixture of all different grain sizes from sand on up to cobbles. the angularity and the poor sorting indicate that this material has not traveled very far from the source area and was probably shed from the active fault scarp as the basin was down-dropped. sedimentologists have concluded that this fault activity could itself have created the ridge basin. owing to a bend in the san gabriel fault, movement would have stretched the crust in the area of the basin, causing it to sag downward. through careful field work combining the study of sedimentary rocks with local tectonic history, geologists have reconstructed a detailed view of the ancient ridge basin. geologists use their understanding of sedimentary rocks to do more than reconstruct the history of the earth's surface. most of the economically valuable resources that are extracted from the earth's crust come from sedim

the research tunnel is in a sedimentary rock formation at a depth of 350 meters. agency experts will soon begin placing simulated nuclear waste containers in alcoves leading off the tunnel. the vessels are equipped with heat sources that keep them at up to 100 degrees celsius to imitate radioactive waste. researchers will check whether nuclear materials stored at such a site is affected by temperature fluctuations, water seepage and other factors. they'll also check whether the tunnel itself sustains any damage. >> translator: the data will be obtained for various conditions associated with the radioactive waste. it will be the first test of its kind in japan. and the data may help to establish a place to store nuclear waste safely. >> also on monday, the industry ministry launched a panel to reexamine its plan to build such underground disposal sites for atomic energy waste. the review is the first in 14 years. the expert panel consists of eight academics specializing in earthquakes, seismic faults, groundwater and other fields. >> translator: we will conduct a t