Cascadia's Fault - Jerry Thompson [101]
A cargo of thirty tons of rice, bound for the capital in Edo, was destroyed and two crewmen were killed. In what amounts to a police report, the boat’s captain and two villagers wrote descriptions of the sinking and petitioned a district magistrate to certify the circumstances of the accident that ruined 470 bales of rice thought to be owned by two samurai from the north coast. The official port certificate absolving the crew of responsibility for the Nakaminato shipwreck of January 28, 1700, was among the documents dug up and examined by Satake, Atwater, and their colleagues.
One village headman, writing his eyewitness account, described seven surges of water that moved “with the speed of a big river.” He took the precaution of sending elders and children to the safety of higher ground at a local shrine and then consulted village elders about the puzzling lack of an earthquake.
Kenji Satake arranged to meet me in the seaport city of Tanabe, southernmost of the six communities where records of Cascadia’s wave had been discovered. In 1997 Tanabe had a population of 72,000. From a distance the harbor and skyline, set against a range of low, blue-green hills and small mountains, looked to me a lot like the coast of southern British Columbia, where the orphan tsunami was born.
Tanabe was badly shaken in 1946 by the magnitude 8.1 subduction rupture along the Nankai Trough, less than sixty miles (100 km) away. The tsunami that hit the harbor only a few minutes later swept 145 homes away, damaged or destroyed 1,200 more, and killed 69 people. Smudgy black and white photos of the aftermath look similar to those from Phuket and Banda Aceh in 2004—jumbled piles of splintered lumber and debris, fishing boats tossed high and dry, stunned survivors looking lost, wandering in the rubble.
A group of city officials took us up a stone stairway leading to an ancient temple on high ground. Twenty steps up the mountain we saw a monument to the dead, engraved with a notch in the marble tablet to indicate the high-water line of the 1946 tsunami. I tried to picture a wall of water high enough to touch the eaves of a two-story building, because that’s how far up it looked to me. Satake and his team compared the 1946 inundation zone to descriptions of the 1700 Cascadia waves and concluded that they had probably reached this height as well.
Tanabe’s mayor in 1700, a member of the Tadokoro family, lived in the merchant district, north of and slightly uphill from the old walled castle. The city’s population then was roughly 2,600 people. The mayor himself escaped the worst effects of the rising water because the flood stopped roughly five hundred feet (150 m) below his home. As an eyewitness, Tadokoro collected and supervised the writing of the official damage reports.
With brushes and black ink faded only slightly after three hundred years, he or his scribe told the scary story in fluid, artistic strokes. When we arrived to film the evidence, Japan’s seismic historians had already searched thousands of pages of the city’s official ledger as well as the Tadokoro family’s “diary of ten thousand generations” to find the orphan tsunami. Complex ideograms flowed in neat, vertical columns on washi, a traditional acid-free paper strengthened with fibers of bark. Over the course of more than three centuries the smooth, durable pages had survived water damage and were perforated here and there by bookworms. But the essential details remained.
The rising Pacific surge flooded the castle moat and ruined nearby paddies and fields of wheat. It soaked and destroyed bales of rice stored in several government warehouses. In those days rice was almost the same as money. On behalf of the shogun, samurai collected