Mass Wastings in Japan

As the book says, slopes are the world's most common landform and Japan is no exception.  Being composed of 70% slopes, Japan experiences mass wastings usually following high rains. Water is a major cause for mass wastings by eroding slope bases, increasing the driving forces for a landslide, as well as increase the weight and underground water pressure of the earth material which, in turn, reduces resistance to slow a landslide as it descends. As with citizen knowledge and preparations for other disasters, Japan has a heightened awareness for mass wastings that has been unfortunately raised by first negatively experiencing destructive landslides. The preemptive landslides from four years ago helped to create warning systems and plans that saved lives from this last summer's onset of monsoon-induced landslides. On August 20, 2014, Hiroshima in particular experienced terrible, deadly landslides following a rainy summer season, where over 400 residential homes were buried and 77 deaths was reported from just one of the city's eight wards (neighborhoods). After this experience, governments of Japan's western prefectures have invested more time and resources into predicting landslides in order to expedite evacuations.

Hiroshima residential warning system devised after deadly 2014 rains drawing wider interest
Hiroshima Asakita Ward Damage From August 20, 2014, Landslide

These efforts are not standardized, however, with many other authorities not sending out mandatory evacuations that are subsequently ignored by citizens who feel above the risk. Though the government could boast that 5 million evacuation warnings were sent out in early July 2018, one article listed the warnings' faults where many ignore the alerts, used to severe but not deadly disasters, that the warnings are sent at odd times, or the responsibility to send the warnings are given to officials with no disaster/evacuation training. Of the 66 deaths were reported from the July 2018 monsoons, the majority were those who ignored warnings. Again, those who survive the worst of these disasters are often the few who make active efforts to avoid or protect against them in the future.

Certain areas found great success in their warning systems this last summer where, at the beginning of July, the region surrounding Hiroshima again faced "thousands" of deadly mass wastings and floods following historical, torrential rainfall. In 2014, Hiroshima officials attempted to distribute complex evacuation plans but the effort was unsuccessful for some as areas started to experience blackouts. As a result, buildings like the Shindate residential complex, invested in rain gauges where "warnings [are] sent by email when 10 millimeters of rain is logged over a 10-minute span, 40 mm over an hour, or 80 mm over three hours." Additionally, regional preparedness agencies are working to create systems that quickly warn citizens, allow people to mark themselves safe, alert authorities of elderly or disabled residents that need assistance, and use QR codes so people can quickly access evacuation and safety information. This privatized warning system sent notifications 46 minutes earlier than government warnings were issued in July. The success of the Shindate complex has spread though, with other private residences and the government alike adopting it's safety practices.

A resident is rescued from a submerged house in Kurashiki.
Rescue Mission in Hiroshima following Landslides and Flooding, July 2018

Sources Used:



Comments

  1. Ana GGOctober 13, 2018 at 1:46 PM

    Great research. I appreciate the fact that this country is always using latest technology and warning systems for pretty most hazards...great to see it is possible to be notified almost 1h beforehand...that is plenty of time to plan/evacuate...

    ReplyDelete
  2. UnknownOctober 15, 2018 at 11:08 AM

    Hello Madeleine,
    Thank you for the mass wasting information about Japan. I knew that this country would be major for this section due to, as you mention, heavy rains and 70% of terrain being sloped. I was not aware that some people in the area do not listen to the warnings sent out by the government. I think for a warning system, like that employed in Japan, to be successful the citizens need not ignore them and head to safety. I like the idea of "regional preparedness agencies" because in my country of study (Fiji) similar situations are needed that these agencies may be able to aid.
    -Daniel Mendoza

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