Seismologists were dealt a bitter blow in failing to anticipate the magnitude-9.0 earthquake occurring in the Tohoku region in 2011, not taking history into account.
Seismologists were dealt a bitter blow in failing to anticipate the magnitude-9.0 earthquake occurring in the Tohoku region in 2011, not taking history into account.
So, in an "unprecedented" move in December, the University of Tokyo’s Earthquake Research Institute started searching for a researcher with the ability to decipher historical archives on earthquakes and volcanoes.
The move by one of the nation’s seismology leaders is in line with a new policy crafted by the education ministry council in 2013, in the aftermath of the Great East Japan Earthquake and tsunami two years earlier.
The policy calls for seismological research incorporating the results of study in the humanities as well as the social sciences to identify powerful temblors and other disasters that have occurred in the country.
With a new approach, Japan, one of the most quake-prone nations in the world, could devise safeguards and responses to mitigate the loss of life and infrastructure from future disasters.
The March 11, 2011, temblor in northeastern Japan spawned giant tsunami waves, resulting in the number of dead and missing at 18,500.
Scientists had been aware from ancient archives, as well as surveys of geological layers, that Tohoku has been repeatedly engulfed by tsunami triggered by major tremors.
One of the most devastating examples was the massive wave that followed the Jogan Earthquake of 869, which was estimated at 8.3-8.4 on the Richter scale.
But experts did not share in a belief that a magnitude-9.0 event could strike the region.
“We were too preoccupied with established theory,” lamented one seismologist, explaining why they did not foresee an earthquake of that size.
“We did not pay sufficient attention to historical documents and findings by geologists,” admitted another.
Prior to the 2011 Tohoku quake, seismologists focused on the monitoring of tremors and crustal movements, an area of geophysics.
But such observations began only about 100 years ago.
Naoyuki Kato, professor of earth planetary physics at the institute, said interdisciplinary collaborations are needed to formulate more reliable estimates for earthquakes that might hit Japan.
“Just knowledge of history or seismology alone is not enough to make the best use of historical materials,” he said. “We are intending to build a solid network of collaborations.”
After the 2011 quake and tsunami, the scale of megaquakes projected to hit Japan and their possible consequences were significantly revised.
For example, the government’s Cabinet Office updated the magnitude of a massive earthquake likely to strike the Japanese mainland on the Pacific coast from 8.8 to 9.1 in its 2012 report.
The quake is expected to originate along the Nankai Trough, a depression on the seabed that extends from Suruga Bay off Shizuoka Prefecture to areas east of Kyushu. A major quake along the trough has occurred at past intervals.
The Cabinet Office’s projection also put the estimated fatalities at 323,000 from the quake and tsunami, 13 times greater than the previous estimate in 2003.
The revision was made after taking into account geological layers formed by past tsunami and other findings.
While experts are more aware of the need to enhance interdisciplinary collaborations to improve forecast estimates, it remains unclear whether that will occur.
Yasufumi Iryu, president of the Geological Society of Japan, said it is not easy for researchers to work together beyond their professional fields.
“A research program is often associated with the number of posts and funding, so a move will be afoot among researchers to protect their own turf,” said Iryu, who is also a professor of geology at Tohoku University. “As a result, interdisciplinary exchanges and collaborations have been thwarted.”
Similar frustrations are also expressed in other fields.
In addition, an achievement-oriented climate, which is sweeping academia as it is the business sector, discourages such efforts.
In the wake of a devastating disaster, the government usually allocates increased funding for seismological research.
After the 1995 Great Hanshin Earthquake, which resulted in 6,434 deaths, more observatory stations were set up and study of active geological faults was promoted.
A 32.4 billion yen ($276 million) project was launched after the Tohoku quake and tsunami to install monitoring posts on 150 undersea locations along the Japan Trench, which spans the Pacific coast of the Kanto region to Hokkaido. It is designed to reinforce the ability to detect signs of earthquakes under the sea, a seismic detection realm that was considered weak.
But many experts agree that efforts to produce more reliable estimates for massive events are not a shortcut to minimizing the fatalities.
A government report says they can be reduced substantially by retrofitting homes and buildings, taking measures to prevent the spread of fires and speedy evacuation in the event of tsunami. Such steps can be implemented without advances in seismological study.
Even some researchers concur on the need for prioritizing construction of shelters to be better prepared for a catastrophe.
“It would serve the public better if we returned a year’s worth of research funds and let that money be used to build buildings near the coast for people to flee to from tsunami,” Iryu recalled a colleague as saying.
Another question that needs to be addressed in the future is how to draw a line between seismology, which is a basic science, and seismology-related research that is designed to help disaster preparedness.
Issuing warnings for potential disasters is vital in mitigating their impact on humans and infrastructure.
No matter how far scientific study advances, however, false alarms cannot be eliminated.
One of the lessons learned from the Tohoku quake and tsunami is that more damage could follow if local officials and the public wait for official warnings and rely excessively on them.
For example, the Meteorological Agency issued warnings for a 3-meter high tsunami for Iwate and Fukushima prefectures three minutes after the Tohoku quake struck.
But the waves topped 8.5 meters in Iwate and 9.3 meters in Fukushima.
Later, the agency admitted that the “warnings, which proved to be lower than the actual ones, might have contributed to a delay in people’s evacuation in some cases.”
Today, the agency’s initial warnings are based on the largest magnitude that can be anticipated in the specific sea area when a massive earthquake is thought to have occurred.
But while alarms with high figures make people become more vigilant, chances are that the warnings often prove wrong.
The estimated height of tsunami turned out to be accurate only once out of 8.2 warnings issued, according to statistics.
As the number of false alarms increase, fewer and fewer residents tend to evacuate.
“The important thing is to understand that seven out of eight tsunami warnings can be inaccurate,” said Yuki Sakai, professor of quake disaster control at Tsukuba University. “Despite that, people should still evacuate because it is a certainty that one in eight will be accurate.”
Toshitaka Katada, professor of civil engineering at Gunma University, cautioned against over-reliance on authorities’ warnings and stressed the importance of self-evacuation.
“Estimates are just the result of calculations,” he said. “People should not overly depend on them.”
Katada is credited with devising a children’s program to safeguard against tsunami in Kamaishi, Iwate Prefecture. In the 2011 tsunami, most of the children in the city survived the tsunami, fleeing to higher ground immediately following the quake.
(This article was written by Makoto Watanabe and Senior Staff Writer Tairiku Kurosawa.)