11:45 AM - 12:00 PM
[SSS13-05] Examination of the reliability of historical teletsunamis in Japan using literature review
★Invited Papers
Keywords:1420 Chilean Earthquake, 1627 Philippine Earthquake, 1651 Peruvian Earthquake, historical teletsunami, false tsunami
1. Introduction
The NGDC/WDS Global Historical Tsunami Database (GHTD) by the National Center for Environmental Information (NCEI) includes thirteen tsunami cases recorded in Japan, accompanied by foreign earthquakes until 1900 (Table 1). Of these, the tsunamis in Japan caused by the 1586 Peru earthquake [Hayashi et al. (2018)] and the 1780 Urup Island earthquake [Hayashi (in print)] were determined to be false teletsunamis upon literature review. This study reviews the literature on three additional cases currently classified by the GHTD as indefinite tsunamis (Table 1).
2. Results of the Literature Review
(1) September 6, 1420—Chilean earthquake
"Shinmei-Kyou,” a Japanese chronicle established in the 15th century, describes the drying up of the sea and is interpreted as a tsunami in the Ibaraki Prefecture by "Dai-Nihon Jishin-Shiryou” (1941). Tsuji (2013) speculated that this was a teletsunami resulting from an earthquake in Peru or Chile because the chronicle did not mention any ground shaking before the sea dryed up. However, "Shinmei-Kyou" only describes seismic events during and after 1420 near Kamakura; thus, obtaining a record of an earthquake is challenging even if there was significant seismic activity before the sea dried up. Therefore, it is erroneous to interpret that there was an earthquake in Peru or Chile on September 6, 1420, or that there was a teletsunami that struck the Ibaraki Prefecture on that date.
(2) September 14, 1627—Philippine earthquake
Iida (1984) linked the Japanese record of the ground motion and tsunami on September 14, 1627, with the Philippine earthquake in the same year. The origin of the Japanese record can be traced back to a description in "Awa-shi" [Saito (1908)], but no contemporaneous historical record can be confirmed. However, the interpretation by Iida (1984) is incorrect as "Awa-shi" states ground motion and tsunami were present in Awa. In addition, although references, such as Perrey (1860), describe the earthquake and tsunami in the Philippines as occurring in August or September, there are no known sources that specify the date of occurrence. Therefore, the 1627 Philippine earthquake and tsunami in Chiba Prefecture are unrelated, and the date of the earthquake can only be specified in terms of the month.
(3) 1651—Peruvian earthquake
No known historical sources indicate that tsunamis in Peru or Chile were caused by the 1651 earthquake. An oral inscription in " Dai-Nihon Jishin-Shiryou” (1941) states that "Kaisho,” an old Japanese word meaning sea level disturbances including storm surges and tsunamis, was in Keian 4 (1651) in Higashiura, Miyagi Prefecture. Iida (1984) introduced two theories, one interpreting this occurrence as a wind tsunami and the other refuting it as a tsunami from South America; however, all cited documents do not positively regard it as an earthquake tsunami. In addition, the notes in "Miyagi Kaiho-shi" [Miyagi Prefecture (1903)], which is the first written version of the oral inscription of the tsunami, indicate that the original information was based solely on one narrator, has a wide range of approximately 10 years, and does not specify the type of phenomenon. This oral inscription is far from any documentation indicating a tsunami occurrence caused by an earthquake in that particular year. As mentioned above, no evidence of a tsunami caused by the 1651 earthquake in Peru, including that in Japan, was found.
3. Conclusion
Combined with the results of my previous studies [Hayashi et al. (2018), Hayashi (in print)], these observations indicate that five of the thirteen pre-19th century teletsunamis recorded in GHTD, which struck Japan, were false tsunamis. Through literature reviews, several instances of false tsunami information have been found in GHTD where this information is based on errors in Japanese documents and historical interpretations. This result suggests that the reliability of historical tsunami data cannot be ensured without collaboration among researchers from different parts of the world.
The NGDC/WDS Global Historical Tsunami Database (GHTD) by the National Center for Environmental Information (NCEI) includes thirteen tsunami cases recorded in Japan, accompanied by foreign earthquakes until 1900 (Table 1). Of these, the tsunamis in Japan caused by the 1586 Peru earthquake [Hayashi et al. (2018)] and the 1780 Urup Island earthquake [Hayashi (in print)] were determined to be false teletsunamis upon literature review. This study reviews the literature on three additional cases currently classified by the GHTD as indefinite tsunamis (Table 1).
2. Results of the Literature Review
(1) September 6, 1420—Chilean earthquake
"Shinmei-Kyou,” a Japanese chronicle established in the 15th century, describes the drying up of the sea and is interpreted as a tsunami in the Ibaraki Prefecture by "Dai-Nihon Jishin-Shiryou” (1941). Tsuji (2013) speculated that this was a teletsunami resulting from an earthquake in Peru or Chile because the chronicle did not mention any ground shaking before the sea dryed up. However, "Shinmei-Kyou" only describes seismic events during and after 1420 near Kamakura; thus, obtaining a record of an earthquake is challenging even if there was significant seismic activity before the sea dried up. Therefore, it is erroneous to interpret that there was an earthquake in Peru or Chile on September 6, 1420, or that there was a teletsunami that struck the Ibaraki Prefecture on that date.
(2) September 14, 1627—Philippine earthquake
Iida (1984) linked the Japanese record of the ground motion and tsunami on September 14, 1627, with the Philippine earthquake in the same year. The origin of the Japanese record can be traced back to a description in "Awa-shi" [Saito (1908)], but no contemporaneous historical record can be confirmed. However, the interpretation by Iida (1984) is incorrect as "Awa-shi" states ground motion and tsunami were present in Awa. In addition, although references, such as Perrey (1860), describe the earthquake and tsunami in the Philippines as occurring in August or September, there are no known sources that specify the date of occurrence. Therefore, the 1627 Philippine earthquake and tsunami in Chiba Prefecture are unrelated, and the date of the earthquake can only be specified in terms of the month.
(3) 1651—Peruvian earthquake
No known historical sources indicate that tsunamis in Peru or Chile were caused by the 1651 earthquake. An oral inscription in " Dai-Nihon Jishin-Shiryou” (1941) states that "Kaisho,” an old Japanese word meaning sea level disturbances including storm surges and tsunamis, was in Keian 4 (1651) in Higashiura, Miyagi Prefecture. Iida (1984) introduced two theories, one interpreting this occurrence as a wind tsunami and the other refuting it as a tsunami from South America; however, all cited documents do not positively regard it as an earthquake tsunami. In addition, the notes in "Miyagi Kaiho-shi" [Miyagi Prefecture (1903)], which is the first written version of the oral inscription of the tsunami, indicate that the original information was based solely on one narrator, has a wide range of approximately 10 years, and does not specify the type of phenomenon. This oral inscription is far from any documentation indicating a tsunami occurrence caused by an earthquake in that particular year. As mentioned above, no evidence of a tsunami caused by the 1651 earthquake in Peru, including that in Japan, was found.
3. Conclusion
Combined with the results of my previous studies [Hayashi et al. (2018), Hayashi (in print)], these observations indicate that five of the thirteen pre-19th century teletsunamis recorded in GHTD, which struck Japan, were false tsunamis. Through literature reviews, several instances of false tsunami information have been found in GHTD where this information is based on errors in Japanese documents and historical interpretations. This result suggests that the reliability of historical tsunami data cannot be ensured without collaboration among researchers from different parts of the world.