By SHOJI NOMURA/ ASAHI SHIMBUN WEEKLY AERA
May 01, 2012
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| Naoyuki Yada, associate professor at the Kanagawa Institute of Technology, monitors cats for warning signs of a large earthquake in Atsugi, Kanagawa Prefecture. (Yuki Yamamoto) |
SUSAKI, Kochi Prefecture--Feeling vulnerable to a catastrophe, this coastal city on the island of Shikoku will monitor fish, chickens and other animals for signs of a huge earthquake that could spawn a monster tsunami.
The Susaki city government is following the long-held idea that animals can sense impending disaster. The city said April 5 that it will release details of the monitoring of the animals to the public, but it will not issue evacuation orders based only on their behavior.
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Map data ©2012 Google, SK M&C, ZENRIN
Map data ©2012 Google, SK M&C, ZENRIN
The city’s decision to regularly monitor animal behavior for possible earthquakes came after the central government released its disaster forecast in March.
According to the forecast, Susaki could be hit by a tsunami as high as 23.9 meters if a powerful earthquake strikes with its epicenter around the Nankai Trough, which runs just off the island. The city, with a population of about 25,000, is prepared for only a 7-meter-high tsunami.
(Records showed that such earthquakes have struck the region in 1707, 1854 and 1946.)
After the Great East Japan Earthquake rocked the Tohoku region on March 11 last year, a 3.2-meter-tall tsunami hit Susaki, the highest in western Japan.
The city’s planned animal-monitoring project was announced after a researcher of structural geology who surveyed Shikoku suggested the step at a meeting of the city’s disaster task force in early April.
“I believe we should not dismiss such a measure even if it has not been scientifically proved to be associated with earthquakes,” said Yoshihito Myojin, the deputy mayor who heads the task force. “We are going to flesh out details of the project to minimize the deaths from tsunami to close to zero.”
The monitoring also involves checking underground water levels.
For centuries in Japan, strange animal behavior and other unusual occurrences have been reported before major earthquakes. They are known as macroscopic anomalous phenomena.
Well-known examples include catfish swimming erratically, rats running wild and wells drying up.
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| Catfish's activities are recorded with an infrared ray sensor. (Yuki Yamamoto) |
China is a frontrunner in research intended to establish links between animal behavior and seismic activity, mainly at the Chinese Academy of Sciences, the nation’s top research center, and a wild animal zoo at Peking University in Beijing.
But reports about unusual animal behavior and events have never drawn serious attention from Japanese scientists. They say such incidents constantly occur, regardless of an earthquake.
That perception changed somewhat after the magnitude-7.3 Great Hanshin Earthquake struck the Kobe area on Jan. 17, 1995, killing more than 6,000 people.
After that temblor, numerous reports were provided by people who said they witnessed precursors of the quake.
A book titled “Zencho Shogen 1,519!” (Testimonies of precursors 1,519) authored by Kiyoshi Wadatsumi, professor emeritus at Osaka City University and a geologist, was published in September 1995, carrying about 3,000 such anecdotes. Among them are 1,519 cases reported by citizens in response to Wadatsumi’s request made through the media.
Reports related to living creatures totaled 781--324 about mammals, 281 about birds, 93 about fish, 40 about reptiles and 43 about insects.
The first accounts occurred about a month before the quake and the number peaked on Jan. 16, according to the book.
The episodes include:
- a normally quiet dog barking three hours before the temblor and digging a hole under a fence in the garden to escape (a resident in Kobe’s Nishi Ward);
- two pet frogs kept indoors emerging from hibernation and making croaking sounds three days before the quake (a resident in Osaka’s Higashi-Yodogawa Ward);
- 10 eggs that were laid on Jan. 12 and bought at a supermarket, each containing two yolks (a resident in Osaka’s Higashinari Ward);
- hundreds of mullets measuring about 30 centimeters each swimming up the Akashi river in Hyogo Prefecture on Jan. 15 (a resident in Akashi, Hyogo Prefecture).
The Susaki municipal government is not the only local government in Japan looking at animals for warning signs.
Shizuoka Prefecture began a similar project in 1996, soliciting information from the public through its website. Prefectural officials have yet to decide if they will use the data for disaster countermeasures.
The central government said there is an 88-percent likelihood that a Tokai earthquake, expected off the prefecture and the surrounding area, will strike within the next 30 years.
Some researchers speculate that animals behave differently before disasters because they can detect rising ion levels and changes in electromagnetic waves in the atmosphere that result from tectonic activities. Or they may be able to sense changes in electric currents running deep inside the Earth.
Although macroscopic anomalous phenomena is not considered a serious science, some are continuing their research.
“At this stage, we have no counterargument to arguments that it is just a coincidence,” said Naoyuki Yada, associate professor of thermal engineering and earthquake prediction at the Kanagawa Institute of Technology in Atsugi, Kanagawa Prefecture. “But it seems all animals, including humans, are equipped with the ability to sense a big vicissitude in the environment.”
In his lab, Yada keeps two cats, a black one and a white one, with pedometers around their necks to monitor their activities.
They are usually docile, with pedometer readings of only dozens of steps a day.
But they displayed unusual behavior on March 9 last year, two days before the magnitude-9.0 earthquake struck northeastern Japan.
The count was nearly 400 for the white cat and around 500 for the black cat, even though they had been put in a cage that day.
When an aftershock measuring an upper 5 on Japan’s seismic scale of 7 shook Chiba Prefecture on the night of March 14, the counts for the white cat and black cat were 319 and 251, respectively.
Lungfish, goldfish, catfish and rats in the lab, which are observed with infrared ray sensors, were found dozens of times more active than usual.
Yada started studying animals for possible precursors 18 years ago. He conducted research under Wadatsumi, who died in January 2011.
Yada’s research found that the chances of an earthquake occurring within three days after cats showed erratic behavior, which is defined as more than 300 counts, are 64 percent for the white cat and 74 percent for the black cat.
Catfish’s accuracy rate tops 80 percent when at least 200 counts were recorded. Fish activity is counted each time it crosses the place where an infrared ray sensor was installed in the tank.
“The only way for us to lead to successful earthquake prediction through animals is to discover regularities by accumulating data piece by piece,” he said. “We are still in a stage before that.”
Yada this year began a project to send free kits to raise catfish to junior high and senior high schools across Japan to create a network of observation points.
He plans to release details of the monitoring activities on the Internet.
Since 1965, the central government has spent about 300 billion yen (3.7 billion) on research for earthquake predictions. But it has so far failed to produce tangible results.
By SHOJI NOMURA/ ASAHI SHIMBUN WEEKLY AERA
