Tree ring information and rainfall characteristic for landslide in the Kobe District, Japan

Abstract

Heavy rainfall on the south side of the Rokko Mountains has often caused severe landslides and debris flows. Analysis of the annual summation of rainfall in excess of 100 mm/day shows that the rainfall in this area has dominant periodicities of about 25-30, 10-13, and 5-7 years. The period of about 25-30 years corresponds to that of occurrence of the natural disasters produced by heavy rainfall; years when the maximum rainfall correspond to years when there have been severe landslides and debris flows in the area. Temporal change in this rainfall may provide a first approximation for erosional force. Analyses of tree ring width from these mountains indicate that the sequences have a dominant periodicity of about 25-30 years. Cross-spectral analyses for rainfall and ring width in this area show high coherency for the periods of about 25-30 years; evidence that variations in the ring width may be used as proxy data for erosional force.

Spatio-temporal analysis of a complex landslide in the Northern Apennines (Italy) by means of dendrochronology

“…The relationship between the triggering of landslides and rainfalls depends on the characteristics of movements: shallow landslides are triggered by heavy rain falling in the preceding hours or days, while deeper landslide are usually related to the rainfall amount over previous weeks or months, and deep-seated movements can even be related to the yearly amount of precipitation (Kashiwaya et al, 1987(Kashiwaya et al, , 1989Wieczorek, 1996;Pasuto and Silvano, 1998;Terlien, 1998;Corominas and Moya, 1999;Flageollet et al, 1999;Polemio and Sdao, 1999;Zezere et al, 1999;Ocakoglu et al, 2002;Schuster and Wieczorek, 2002). There are no data about the depth of the studied reactivations but we know that the main sliding surface is set at a mean depth of 20 m. Then we analysed the cumulative rainfall amount for 1, 15, 30, 60, 120 and 180 days, taking into account that the reactivations could have involved either the whole depth of the landslide or a shallow portion.…”

Mouvements de masse et dynamique d’un géosystème alpestre : étude dendrogéomorphologique de deux sites de la vallée de Boulc (Diois, France)

“…Plusieurs auteurs ont montré en effet le rôle des facteurs climatiques dans le déclenchement des mouvements (Caine, 1980 ;Kashiwaya et al, 1989) en particulier dans les Alpes du sud (Julian et Anthony, 1993), où les précipitations sont fréquemment concentrées dans des courtes averses de forte intensité ou dans des rafales soutenues pendant plusieurs jours.…”

Earthquake‐related geomorphic environment and pond sediment information

“…With this question in mind, we set out two sediment traps in one pond of the Kobe district immediately after the earthquake, in order to learn about the earthquake's influence on surface processes, to learn how long this influence lasted, and to determine the differences between hydrological and seismic phenomena because we had studied hydrogeomorphological phenomena recorded in the same pond (Kashiwaya et al, 1988(Kashiwaya et al, , 1995. The Kobe district often experienced episodes of disastrously heavy rainfall prior to the 1995 earthquake (Kashiwaya et al, 1989;Kashiwaya and Okimura, 1990). More than 400 people were killed by rapid mass movements during heavy rainfall in 1938, and about 100 people were killed in 1967 (Tanahashi et al, 1939;Okimura and Torii, 1997).…”