Cases of Disaster

Process of Landslide and Initial Measures

This large-scale landslide featured a short-term sliding, two days from the detection of its indications to slipping. Under this situation, proper initial measures against the landslide, based on a combination of administrative staff and local people, could prevent human damage.

Initial measures against landslide in Taniya

Date Time Field status Initial activities
Nov. 14(THU) 9:00- It was reported that cracks of a temporary road and the surface displacement of the bottom paddy field were found. On-site investigation was conducted by Sabo dam contractors, a civil engineering office and consultants.
18:00 Unclear faulting was detected on the surface of the top rice field. Discussions with the civil engineering office were made. (It was pointed out that the landslide could develop to a large-scale disaster.)
Nov. 15(FRI) A.M. Cracks occurred over an extensive area. Due to that cracking and faulting started to become clear, continuous and emergent communications were established.
14:30   Shuttering boards were installed. (4 points)
17:00 Discussions with Himi city were made.
The current situation was reported to the Himi Police and Fire Department.
19:00   Briefing for residents (The mayor and the head of the civil engineering office attended to the meeting.)
3 households, 15 people evacuated voluntarily.
Nov. 16(SAT) 7:30   Water in the reservoir was drained.
10:30   Shuttering board: 50-100 mm/20 h
Variations over time: 2.5-5 mm/h
14:00   Briefing for local people (The head of the civil engineering office and the vice-mayor attended to the meeting.)
16 households, 76 people evacuated voluntarily.
14:30   The Toyama Work Office was requested to install monitoring cameras and floodlight cars .
16:00   The "Landslide Alert Center in Taniya Area, Himi City" was established.
22:15 Rocks fell.  
22:30   The National Road Route 415 was closed
22:45 Landslide occurred Lighting of field floodlight cars went out.
Nov. 17(SUN) 6:30   On-site investigation was launched.
It was confirmed that 1 house was completely destroyed while 1 house was half destroyed.
8:00   The "Landslide Alert Center in Taniya Area, Himi City" was shifted to the "Landslide Disaster Countermeasures Office in Taniya Area, Himi City."
Nov. 18(MON) 11:00   Joint survey with the Independent Administrative Institution Public Works Research Institute (IAI-PWRI) was conducted.
15:00   1st Project Team (PT) meeting
Nov. 20(WED) 10:30   2nd PT meeting
    The construction of a bypass road for the Route 415 and guard dams and horizontal boring for drainage were started.
Nov. 21(THU) 11:40   The Toyama governor visited the site.
Nov. 27(WED) 8:40   The second joint survey with the Independent Administrative Institution Public Works Research Institute (IAI-PWRI) was conducted.
22:00   Building of guard dams was completed.
Nov. 28(THU) 15:30   3rd PT meeting
17:50   Himi City's Meeting on the Landslide Disaster Countermeasures
18:00   An evacuation order on local residents except 3 households below the slope was lifted.
19:00   A closure order on the National Road was lifted.
Finding cracks of a temporary road
Finding muddy pool within a torrent
The mayor requested local people to evacuate voluntarily at a briefing.

Proper Warning and Evacuation Points on Landslide Disasters in Taniya Area

  1. Unusual situations were detected earlier.
  2. Proper and immediate investigation on landslide was conducted.
  3. Earlier reports to the Himi Mayor and immediate top judgment were implemented.
  4. Earlier reports to the local residents were conducted.
  5. There were some people in evacuating families that suffered from landslide disaster in the past
  6. Disaster prevention measures using IT were taken.

Monitaring camera on the other side of the river

Monitoring system in a shelter

Temporary horizontal boring drained water of 200 liter or more per minute.

Installment of horizontal drainage boring hole

tentatively constructed block wall against debris flow

Monthly precipitation in 2002 (Himi local meteorological observatory)