Demonstration test on the easily comprehensive information for the early
warning against sediment]related disastersa
Takao YAMAKOSHI, Jun'ichi KURIHARA, Keiji TAMURA, Naoki JAJIMA, Tadao OTANI,
Nobuhiro USUKI and Osamu SAGUCHI
Abstract
Early warning is important to prevent sediment]related disasters. However, reality
is that it is difficult for local authorities to issue evacuation order and also
difficult for residents to evacuate even if it would be issued. Therefore, it
is critical to provide easily comprehensive information which can contribute to
immediate judgment of local authorities and self]imposed evacuation by local residents.
In this study, we prepared a portal site for early warning against sediment]related
disaster through internet and cellular phone data communication system (i]mode).
For one year, we kept providing the information through the portal site to the
selected local government officers, members of volunteer fire service, and residents
all who have a leading role at the time of disaster as a demonstration test. Information
on the risk of sediment]related disaster, radar rainfall data, and ground]based
rainfall data are all provided in real]time. If the amount and intensity of rainfall
exceed a previously designated value, alert mails are sent. During and after the
test, we had questionnaires on the information provided to the examinees. As a
result, the following is clarified. 1) Throughout the test, there was no serious
rainstorm which is large enough to trigger landslide. However, we confirmed that
the information provided sometimes triggered the examinees to make actions such
as a patrol around their town. 2) The i]mode system was utilized much more frequently
than internet, 3) The number of accesses to the radar]rainfall data was largest
in all the provided contents. 4) The wider view of the information on the risk
of sediment]related disaster was preferred. 5) The timing of the alert mail is
important.