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[O11-P68] Earthquakes that occurred between 1898 and 1924 as read from diaries in Tokorozawa, Saitama and the value of diaries
Keywords:earthquakes that occured between 1898 and 1924, diary to remain in Tokorozawa City
Background and Purpose of the Study
The author, a member of a high school science research club, has been involved in documenting the impact of the 1923 Great Kanto Earthquake in Saitama Prefecture. This study focuses on seismic records in Tokorozawa City, particularly using three historical family diaries—Kitada, Moroboshi, and Suzuki—which were kept daily and offer insights into both the earthquake and the recovery process.
The aim of this research is to analyze earthquakes other than the 1923 Great Kanto Earthquake using these diaries. The study examines how the diaries reflect the perceived shaking intensity in Tokorozawa, correlating those descriptions with the location and magnitude of each earthquake. It also investigates how effectively such historical documents can replicate the strength and duration of earthquake shaking.
Methodology
The study uses the following diaries: Kitada Family Diary (1898–1924)
Moroboshi Family Diary (1906–1924)
Suzuki Family Diary (1906–1964, photograph reproduction)
The research period was limited to 1898–1924, aligned with the more detailed Kitada diary. Earthquakes included in the analysis were selected based on clear epicenter and timing data from Usami (2003), “Latest Catalogue of Damaging Earthquakes in Japan”. A total of 134 earthquakes from this period were reviewed, including potential foreshocks and aftershocks within a five-day range.
Findings
Out of the 134 earthquakes, the Kitada diary documented 20, Moroboshi 6, and Suzuki 3. Kitada often labeled M6+ events as “large earthquakes,” while Moroboshi and Suzuki did so only for M7+ events. Earthquakes with epicenters far from Tokorozawa, such as in Shizuoka or Mie, were less likely to be described as significant unless they exceeded M7. Damage in Tokorozawa was noted in a few events, particularly those close to Saitama or neighboring prefectures.
Interestingly, nearly all epicenters of the documented earthquakes were south of Tokorozawa (latitude 35.8°N). Comparison with modern seismic data (post-2016) showed similarities, especially for earthquakes in southern Ibaraki and northern Saitama. Expressions like “long shaking” in the Kitada diary corresponded with longer-duration seismic waves in modern records, confirming that the diary captured the earthquake’s duration rather than frequency.
Future Prospects
Given the high number of entries in the Kitada diary, further research is planned to explore additional time periods and potentially uncover more earthquake-related descriptions.
The author, a member of a high school science research club, has been involved in documenting the impact of the 1923 Great Kanto Earthquake in Saitama Prefecture. This study focuses on seismic records in Tokorozawa City, particularly using three historical family diaries—Kitada, Moroboshi, and Suzuki—which were kept daily and offer insights into both the earthquake and the recovery process.
The aim of this research is to analyze earthquakes other than the 1923 Great Kanto Earthquake using these diaries. The study examines how the diaries reflect the perceived shaking intensity in Tokorozawa, correlating those descriptions with the location and magnitude of each earthquake. It also investigates how effectively such historical documents can replicate the strength and duration of earthquake shaking.
Methodology
The study uses the following diaries: Kitada Family Diary (1898–1924)
Moroboshi Family Diary (1906–1924)
Suzuki Family Diary (1906–1964, photograph reproduction)
The research period was limited to 1898–1924, aligned with the more detailed Kitada diary. Earthquakes included in the analysis were selected based on clear epicenter and timing data from Usami (2003), “Latest Catalogue of Damaging Earthquakes in Japan”. A total of 134 earthquakes from this period were reviewed, including potential foreshocks and aftershocks within a five-day range.
Findings
Out of the 134 earthquakes, the Kitada diary documented 20, Moroboshi 6, and Suzuki 3. Kitada often labeled M6+ events as “large earthquakes,” while Moroboshi and Suzuki did so only for M7+ events. Earthquakes with epicenters far from Tokorozawa, such as in Shizuoka or Mie, were less likely to be described as significant unless they exceeded M7. Damage in Tokorozawa was noted in a few events, particularly those close to Saitama or neighboring prefectures.
Interestingly, nearly all epicenters of the documented earthquakes were south of Tokorozawa (latitude 35.8°N). Comparison with modern seismic data (post-2016) showed similarities, especially for earthquakes in southern Ibaraki and northern Saitama. Expressions like “long shaking” in the Kitada diary corresponded with longer-duration seismic waves in modern records, confirming that the diary captured the earthquake’s duration rather than frequency.
Future Prospects
Given the high number of entries in the Kitada diary, further research is planned to explore additional time periods and potentially uncover more earthquake-related descriptions.