Protecting Japan from tsunamis
As Japan begins to rebuild after the massive 9.0 magnitude earthquake and tsunami, engineers are beginning to analyze the destruction to learn how to better prepare for future natural disasters; one expert says that prior to the earthquake, more infrastructures spending, particularly for projects aimed at preventing the approaching tsunami, could have mitigated much of the damage; the tsunami easily overwhelmed one of the tallest and longest seawalls in Japan; officials will have to decide whether to reinvest in costly tsunami infrastructure or to relocate communities further from the ocean to minimize the numbers affected by such events
As Japan begins to rebuild after the massive 9.0 magnitude earthquake and tsunami ravaged much of the country’s north-east, engineers are beginning to analyze the destruction to learn how to better prepare for future natural disasters.
One expert says that prior to the earthquake, more infrastructures spending, particularly for projects aimed at preventing the approaching tsunami, could have mitigated much of the damage.
“We cooperate with the government on tsunami countermeasures, but there has been less financing and sometimes there isn’t enough for the construction of structural measures,” Imamura said. “Now, the government’s focus has shifted to non-structural measures, because they are cheaper.”
These measures have included printing maps which show areas that lie at a lower elevation.
Imamura, who has been studying tsunamis for nearly thirty years, says that the 11 March tsunami that struck Japan was far worse than anything scientists had anticipated as they never expected such a massive earthquake.
The tsunami easily overwhelmed Taro’s sea wall, dubbed Japan’s “Great Wall of China” as one of the tallest and longest seawalls in Japan.
Roughly fifty miles south, the city of Kamaishi had even more elaborate tsunami infrastructure and preliminary analysis suggests that it helped to minimize damage.
Two years ago, Kamaishi completed the world’s deepest breakwater at 207 feet deep. Construction took three decades and $1.5 billion. In addition to the breakwater, Kamaishi had also built several sea walls and other facilities designed to shield the city from the impact of a tsunami.
While the breakwater has been significantly damaged, with sections of it floating in the harbor, it is believed to have helped blunt the force of the tsunami.
According to Shoichi Sasaki, an official at Kamaishi’s Ministry of Land’s office, “the damage was limited, compared to other places.”
As officials rebuild Japan, they will have to decide whether to reinvest in costly tsunami infrastructure or to relocate communities further from the ocean to minimize the numbers affected by such events.
Imamura suggests moving towns further inland.
“We are living very close to the coast. The fishing industry needs to be near the coast, but living areas and other facilities need to be farther in,” he said.
He added, “We need land-use planning.”
Imamura also suggested planting more pine and mangrove trees along the coast to slow down the tsunami in addition to more evacuation shelters that can withstand the impact of waves.
