BOOK: Orphan Tsunami of 1700

Atwater, Brian F. et al. The Orphan Tsunami of 1700: Japanese Clues to a Parent Earthquake in North America. U.S. Geological Survey professional paper, 1707. Reston, Va.: U.S. Geological Survey; Seattle: In Association with University of Washington Press, 2005.

This report, available both for purchase as a book and as a downloadable pdf on the US Geological Survey’s website (http://pubs.usgs.gov/pp/pp1707/), combines documentary and geological sources with modeling in an attempt to give a full account of a tsunami thought to have been generated by an approximately 9.0 M earthquake originating in the Cascadia subduction zone on January 26, 1700. While the initial announcement of the connection between that 18th-century Japanese tsunami and the Cascadia fault – known as an “orphan tsunami” by researchers because it was not preceded by a locally felt earthquake – was announced in Nature in the 1990s, it is hard not to see a connection between the publication of this 2005 report and the 2004 Indian Ocean tsunami, although that disaster is only mentioned in passing. The report and its underlying research emphasize the disaster potential of the Cascadia fault zone by relating a catastrophic past seismic event. The presentation of the findings and the style and language used only underlines that this report was aimed at alerting the general public to potential risk. The result is a very detailed reconstruction of a historical tsunami that could probably be easily given to an undergraduate or advanced high-school audience.

The report is divided into three sections. The first presents the geological evidence for a massive Cascadia earthquake and local tsunami, accompanied with related folklore accounts presenting a potential Native American memory of the event. The second section presents the Japanese accounts of the tsunami impact (although, as the wave was not preceded by a local earthquake, many of these accounts do not call the event a “tsunami”). The third section presents the authors’ case for the connection between the two events, although this connection has been assumed as a fait accompli throughout the work. Much of the second and third sections compare the Cascadia event to the 1960 Chile earthquake and tsunami, as the authors have taken the latter as a model for the former. Pictures and data from the 1960 tsunami therefore stand in for the 1700 event and add urgency to the authors’ call for better preparation for the future Cascadia megathrust quake which they are sure will come.

Oddly, for a work aimed at a general audience, the information about the Japanese documents is very detailed, including images of many primary sources, some of them glossed word-for-word. While glossing the documents instead of translating them makes them harder to parse for a general reader, this presentation means that this book could almost be used as an introduction to certain types of early modern Japanese sources. Also present in this report, although not as emphasized, is some of the background behind the study of historical earthquakes and tsunami in Japan, which has also benefited from a long-standing collaboration between historians (both academic and amateur) and seismologists in Japan. – Kristina Buhrman

Additional readings:

Satake, Kenji, Kunihiko Shimazaki, Yoshinobu Tsuji, and Kazue Ueda. 1996. Time and size of a giant earthquake in Cascadia inferred from Japanese tsunami records of January 1700. Nature 379, no. 6562 (January 18): 246-249. doi:10.1038/379246a0.