Coastal Hazards

Japan being an island is no stranger to coastal hazards, in fact there a little hazards this resilient nation doesn't face, and like most islands in the pacific, Japan is struggling with the current rise in sea level which has massive ramifications for a country with a coastline that is almost 30,000 km long.

This rise in sea level for Japan is a huge threat as the majority of its land mass and population is coastal.  In a 1996 research paper titled “Responses of Coastal Topography to Rising Sea Levels,” climate scholars Nobuo Mimura and Eiichi Kawaguchi forecast that a 1-meter rise in sea levels would cause 90.3 percent of the country’s sand beaches to erode not only is the loss of coastline worrisome but it would also mean larger wave action hitting the shoreline and causing further damage.  A 1-meter rise in sea levels on the country’s coastline would be devastating to the economy, with almost 80 percent of the country’s commercial sales and roughly half of its population and industrial production located in coastal areas.

Not only is the rising sea level a problem but also erosion of Japan's shoreline is taking a toll on the country, As a result of the abnormal amount of man made coastal structures and alterations like dams, fishing and commercial ports the continuous sand that would usually make it way down to the beaches is now slower moving and trapped.

Osaka Prefectural Government "What Results From Global Warming?" http://www.pref.osaka.lg.jp/kannosuisoken/apec/results.html

Takaaki, Uda "Japan's Beach Erosion" Public works reaserch center, Japan.  Volume 31. (Pg. 228-243)  http://www.worldscientific.com/worldscibooks/10.1142/7332

Johannsson, Elena K.  Jul 12,2014. "Rising Tide: Long-term Ramifications of Global Warming on the Country's Coastline."  The Japan Times.    http://www.japantimes.co.jp/life/2014/07/12/environment/rising-tide-long-term-ramifications-global-warming-countrys-coastline/#.VUcNHPldVqU

Extreme weather

Being located in the pacific northwest Japan is no stranger to extreme weather, which includes typhoons. Typhoons also known as hurricanes are most common in Japan between May and October with August and September being the peak season.  The hardest hit are typically the smaller islands but the main island is usually hit by a couple a year as well.  

Typhoons vary greatly in their strength and potential hazard to the island.  Luckily, they are slow moving storms which makes their direction easy to predict and makes accurate early warnings given to the citizens possible.

Flooding from a Typhoon

Most deaths from typhoons are actually caused by the rapid rise in sea level and landslides, but the death tolls in recent years have been much lower thanks to Japan's early warning system run by the Japan Meteorological Agency who tracks the storms in real time and give updates on their locations.  

"Japan Meteorology Agency" Tropical Cyclone Information. http://www.jma.go.jp/en/typh/

Subsidence

The subsidence hazard in Japan has actually greatly decreased over the years thanks to new laws and ordinances that restrict groundwater pumping in soft ground.  Although there has been a slight increase from the recent low due to the nation-wide dry spell Japan is experiencing.  but they continue to protect their citizens from threats like sinkholes by placing informative signs to make citizens aware of dangerous areas and enforcing their ordinances on pumping ground water in sensitive areas.  

Tsunamis are nothing new to the people of Japan, in fact the word tsunami originates there, with the word for harbor (tsu) and wave (nami).

High seismic activity off the coast of Japan are the cause for this threat of tsunamis, when the earthquake causes the seafloor along the fault suddenly shifts vertically, this motion shifts the water column above and is what creates the tsunami.  Anytime there is a high magnitude earthquake there is a risk it could be followed by a tsunami.  The Tsunami Warning Network determines the risk after each quake by determining whether a vertical shift occurred at the fault and by looking at measurement ofs water height recorded around the Pacific Ocean by the TWN (Tsunami Warning Network).  

Japan does everything it can to protect themselves from the threat of tsunamis.  They have implemented an earthquake warning system that sends out texts to phones and emergency broadcasts to TVs.  Also a ocean-based tsunami warning system, where a network of buoys sitting on the seafloor detect changes in water pressure and can detect tsunamis forming, this emits a signal to the warning center where they put out an alert.  

Model of early warning buoys.

Of course you only have so much warning with these types of hazards, In the devastating 9.0 earthquake that struck Japan in 2011 there was only a 80 second warning for the quake and the warning for the following tsunami was a huge under estimation.  To further help protect from tsunamis 40% of Japan's coastline is protected by concrete seawalls ranging from 10-35 feet tall, and the country is currently planning on the construction of vertical evacuation structures for areas most at risk.  

Seawalls being breached in 2011 tsunami in Japan.

                          

Parry,Wynne. "What's the Science Behinf Japan's Quake and Tsunami". Live Science.  Mar 11, 2011.  http://www.livescience.com/

Demetriou,Danielle. "Tsunami two years on: Japan finally gets warning system that would have saved hundreds of lives." The Telegraph. Mar 9, 2013. http://www.telegraph.co.uk/

Knight,Will. "How Japan's Earthquake and Tsunami Warning Systems Work" MIT Technology Review. Mar 11,2011. http://www.technologyreview.com/

10% of the world's active volcanoes reside in Japan, more than any other country, 100 of which are currently active.  These volcanoes are part of the Pacific Ring of Fire and are caused by subduction zones of the Pacific plate beneath continental and other oceanic plates along its margins.

The Japan Meteorological Agency (JMA) provides the nation with early warning information for earthquakes, tsunamis and volcanic eruptions.  Usually the general population will get a decent warning before any threatening volcanic activity since magma flow is easier to predict than an earthquake but of course volcanoes are not 100% predictable and can erupt without warning.  
Which is what happened on September 27, 2014 at the second largest volcano in Japan, Mount Ontake, when volcano classified as a level 1 at the time(normal/nonthreatening) erupted without magma.  At least 56 hikers were killed and many more injured and missing.  In rare cases like this when no prior warning is given there is little that can be down to take precautionary measures.  

Mount Ontake during it's eruption on September 27, 2014

Some of active volcanoes in Japan have now be equipped with reinforced concrete shelters near the crater and along trails for hikers to take shelter in during a sudden eruption.  After the devastation at Mount Ontake which many believe could have been lessened with an adequate amount of shelters the nation want's to increase the amount provided at each volcano but budgeting is currently an issue.  Currently Mount Fuji one of Japan's most popular hiking spots has no shelters in place.  

Concrete shelters

V.Grasso and A.Singh, UNEP (Dec 2011, forthcoming): Early Warning Systems: www.jma.go.jp/jm/en/Activities/earthquake.html,.com

"Volcanoes of Japan" Volcano Discovery.  http://www.volcanodiscovery.com/

A country better prepared than anyone

Japan has a huge amount of seismic activity due to it's close proximity to tectonic plate boundaries.  They have on average 1,500 earthquakes each year, of course many of these are very small but they do experience a few very catastrophic quakes happening each century, The most recent of which occurred in 2011, which was a record breaking 9.0 followed by a horrific tsunami.  


The people of Japan have learned from these past disasters and invest heavily in earthquake and tsunami preparation.  At an early age children in Japan are taught what to do during an earthquake; from diving under desks to staying away from falling debris.  Every office and most houses have an earthquake emergency kits, with food, water, and medical supplies. Offices and school also keep hard-hats and gloves for use in the event of a quake.

Japan has some of the strictest building codes to protect against the larger earthquakes.  With limits of how much a building is allowed to even sway during a quake and most high-rise towers contain extra steel bracing. giant rubber pads and hydraulic shock absorbers, this makes all of Japan's newer buildings some of the safest in the world.  Yet many of Japan's quakes are followed by tsunamis which are a disaster in themselves.  Which is why they've invested in sea walls to protect their most vulnerable areas.  

Glanz, James. Onishi, Norimitsu "Japan’s Strict Building Codes Saved Lives." http://www.nytimes.com/ March 11, 2011Foster, Peter "Japan earthquake: country better prepared than anyone for quakes and tsunamis" http://www.telegraph.co.uk/ 11 mar 2011

Prone to Disaster

Japan is a hot spot for hazards, and considering where it's located it's no wonder why.  Located near major tectonic plate boundaries situated in the Pacific ring of fire; a ring of volcanoes lining the Pacific Ocean as a result from the subduction of the Oceanic plates beneath the lighter continental plates. The ring of fire is home to 75% of the world's volcanoes, 10% which are found in Japan alone and an epicenter for Earthquake activity.  

                                                   world's most active earthquake belt

Pacific Ring of Fire (Not actually on fire)

Japan is spread across four tectonic plates, the Pacific plate, the Philippine plate, the North American plate and the Eurasian plate.  The Japanese Islands are situated in a subduction zone in the northwestern margin of the Pacific Ocean where the Pacific Plate and Philippine Sea Plate are subducting.  

The four plates

Nishiwaki,  Hirotoshi "Introduction to the Landforms and Geology of Japan" 2009 http://www.glgarcs.net/ 

Keller, Edward A. DeVecchio, Duane E. Natural Hazards:New Jersey. Pretence Hall, 2012. Thired Edition