Development of Tsunami Trace Database with Reliability Evaluation on Japan Coasts

Abstract

The purpose of this research is to develop a Tsunami Trace Database by collecting historical materials as well as documents concerning tsunamis which had hit Japan and, of which the reliability of tsunami run-up and related data is taken into account. Based on acquisition and surveying of references, tsunami trace data over past 400 years of Japan has collected into a database, and reliability of each trace data was evaluated according to categorization of Japan Society of Civil Engineers (2002). As a result, trace data can now be searched and filtered with reliability levels accordingly whilst utilizing it for verification of tsunami numerical analysis and estimation of tsunami sources. By analyzing this database, we have quantitatively revealed the fact that the amount of reliable data tends to diminish as it goes older.

Estimating the Topography Before Volcanic Sector Collapses Using Tsunami Survey Data and Numerical Simulations

“…174, (2017) Estimating the Topography Before Volcanic Sector Collapses 3279 in the computations if the observation sites were not inundated. Moreover, the observational data were based on the height information of the Japan Tsunami Trace database (Iwabuchi et al 2012). The observational data in this database are divided into six groups, A, B, C, D, X, and Z, depending on the reliability.…”

“…Thus, it is acceptable to use data in group Z in addition to groups A and B. Group Z means that the information, such as the location, is not quantitative (Iwabuchi et al 2012). Figure 7 shows that the run-up heights at Uchiura Bay are large.…”

The Search for Tsunami Evidence in the Geological and Archaeological Records, With a Focus on Japan

“…However, it also compiles data drawn from historic documents such as field surveys, research reports, and coastal policies that describe 25,664 "traces" (konseki 痕跡) of tsunami. Traces are marks left on buildings, trees, rocks, and so on that indicate run-up heights and inundation distances (Iwabuchi et al 2012). The 3367 traces that are dated before 1887 are categorized as "historic tsunami" traces, while the 22,297 traces dated after 1888 (for which seismic data are available) are called "modern tsunami" traces (Iwabuchi et al 2012).…”

“…Traces are marks left on buildings, trees, rocks, and so on that indicate run-up heights and inundation distances (Iwabuchi et al 2012). The 3367 traces that are dated before 1887 are categorized as "historic tsunami" traces, while the 22,297 traces dated after 1888 (for which seismic data are available) are called "modern tsunami" traces (Iwabuchi et al 2012). Of the modern tsunami traces, 15,079 date since the Chilean tsunami of 1960.…”

“…This database has the unusual feature of "reliability" assessments, carried out by a committee of experts (Satake 2007:488). Different scales of reliability of the collected data in categories A-D (from reliable to increasingly uncertain), X (unreliable), and Z (needs more investigation) were established for pre-and post-1960 events, based on the tsunami from Chile of that year (Iwabuchi et al 2012: I_1327, Table 1 and I_1329, Table 8). From 2007, the committee has conducted quarterly reviews of the reliability of both the documentary/field evidence for tsunami and the database system.…”