Presentation Information
[O12-P10]Diary of the 1923 Kanto Earthquake remaining in Inzai City, Chiba Prefecture
*Karin Kitahara1 (1. Sakae Higashi Senior High School)
Keywords:
1923 Kanto Earthquake,diary to remain in Inzai City,Chiba Prefecture,Earthquake
§1. Introduction
The Science Research Club to which the author belongs has been conducting research on the records of the Great Kanto Earthquake that occurred on September 1, 1923 (Taisho 12) in Saitama Prefecture. In March 2025, the author discovered this ongoing research on the club’s website and decided to join the study. Realizing that many areas in Chiba Prefecture remain unexamined in the field of historical seismology, the author chose to focus on the records of the Kanto Earthquake in Inzai City, where the author resides.
§2. Previous Research
According to Table 1, the damage to wooden houses in Kioroshi-machi (Fig. 1, (1)) and Omori-machi (Fig. 1, (2)) in Inzai City during the Great Kanto Earthquake is reported to have been relatively minor compared to the heavily affected areas of Kawaguchi-machi, Satte-machi, and Kasukabe-machi (now Kawaguchi City, Satte City, and Kasukabe City) (Moroi & Takemura, 2002).
§3. Records within Inzai City
3.1 History of Inzai City, General History Vol. 4: Modern and Contemporary Era
In the History of Inzai City, General History Vol. 4, published by the Inzai City Board of Education in 2024, accounts were found describing the collapse of houses, cracks in the Tone River embankment, and the total destruction of a brick factory. It also noted that the diary of Mr. Muto, who lived in Yoji-mura (Fig. 1, (2)), contained details regarding damage to his home and neighborhood, recovery efforts, evacuees from Tokyo, and rumors of riots involving Zainichi Koreans.
3.2 The Diary of Mr. Muto
The author investigated the diary of Mr. Tameshige Muto, as referenced in the History of Inzai City. Mr. Muto served as a member of the Chiba Prefectural Assembly, and his diary frequently documents financial transactions with local residents and family matters. A distinctive feature of the diary is the recording of weather and wind direction at the start of each entry, and the temperature in the Réaumur scale at the end.
3.3 Earthquakes Recorded in the Diary
Figure 2 shows a photograph of the diary entry for September 1st, and Table 2 lists the earthquakes recorded. Since the Great Kanto Earthquake occurred at 11:58:32 AM, it is assumed that there are some time discrepancies in Mr. Muto's records.
3.4 Rumors of Riots by Korean residents in Japan
Previous research (Shinoda & Arai, 2022) has confirmed that such incidents occurred within Saitama Prefecture (Kumagaya, Honjo, Kamisato, Yorii, Fukaya, etc.), and it was found that similar events took place in Inzai City.
The diary entry for September 4, 1923, states: "On September 4th, at the request of the Kioroshi Police Station to be on alert for 'Korean residents in Japan' , fire brigade members were mobilized and sentries were posted at two locations in the district. The Kato residence was used as an office. We continued standing guard in shifts for about a week thereafter."
3.5 Damage Recorded in the Diary
The following damage was noted:
• Toppling of a stone lantern in the center of the back garden.
• Falling of tea jars, bottles, and cans.
• Clocks stopping.
• Overflowing of the fountain.
• Toppling of the stone pagoda of the guardian deity and other stone monuments.
The extent of damage to a single house and its surroundings suggests significant impact across Inzai City. The diary also mentions that "fires and power outages occurred in the Tokyo direction from September 1st to 3rd." The visibility of these fires suggests they may have reached Chiba Prefecture.
Furthermore, the description of "cracks of 3–9 cm in the ground and subsidences of 6–9 cm" suggests the occurrence of soil liquefaction. According to the Inzai City Liquefaction Hazard Map (Fig. 3), the susceptibility in Yoji-mura (Fig. 1, (2)) ranges from "somewhat high" to "extremely low." While the exact location of the residence is unknown, liquefaction is a strong possibility.
§4. Future Outlook
I intend to identify the specific earthquakes recorded in the diary (Table 2) by comparing them with the findings of Usami (2003).At the 42nd Conference of the Japanese Society for Historical Earthquakes (Toyooka Meeting), researchers suggested a physical approach to estimate the magnitude based on the damage descriptions while considering the context of government censorship of speech. I hope to incorporate these perspectives into my future research.
Acknowledgments
I would like to express my sincere gratitude to the staff of the Inzai City Kioroshi Koryu-no-Mori History Center (Fig. 1, (3)), and to Mr. Taishi Numano of the Science Research Club for his assistance with the diary investigation. I also received invaluable advice from alumni Mr. Yusuke Uemura (40th) and Mr. Haruka Shinoda (42nd), as well as current member Mr. Kouki Tokuda. I hereby record my thanks.
The Science Research Club to which the author belongs has been conducting research on the records of the Great Kanto Earthquake that occurred on September 1, 1923 (Taisho 12) in Saitama Prefecture. In March 2025, the author discovered this ongoing research on the club’s website and decided to join the study. Realizing that many areas in Chiba Prefecture remain unexamined in the field of historical seismology, the author chose to focus on the records of the Kanto Earthquake in Inzai City, where the author resides.
§2. Previous Research
According to Table 1, the damage to wooden houses in Kioroshi-machi (Fig. 1, (1)) and Omori-machi (Fig. 1, (2)) in Inzai City during the Great Kanto Earthquake is reported to have been relatively minor compared to the heavily affected areas of Kawaguchi-machi, Satte-machi, and Kasukabe-machi (now Kawaguchi City, Satte City, and Kasukabe City) (Moroi & Takemura, 2002).
§3. Records within Inzai City
3.1 History of Inzai City, General History Vol. 4: Modern and Contemporary Era
In the History of Inzai City, General History Vol. 4, published by the Inzai City Board of Education in 2024, accounts were found describing the collapse of houses, cracks in the Tone River embankment, and the total destruction of a brick factory. It also noted that the diary of Mr. Muto, who lived in Yoji-mura (Fig. 1, (2)), contained details regarding damage to his home and neighborhood, recovery efforts, evacuees from Tokyo, and rumors of riots involving Zainichi Koreans.
3.2 The Diary of Mr. Muto
The author investigated the diary of Mr. Tameshige Muto, as referenced in the History of Inzai City. Mr. Muto served as a member of the Chiba Prefectural Assembly, and his diary frequently documents financial transactions with local residents and family matters. A distinctive feature of the diary is the recording of weather and wind direction at the start of each entry, and the temperature in the Réaumur scale at the end.
3.3 Earthquakes Recorded in the Diary
Figure 2 shows a photograph of the diary entry for September 1st, and Table 2 lists the earthquakes recorded. Since the Great Kanto Earthquake occurred at 11:58:32 AM, it is assumed that there are some time discrepancies in Mr. Muto's records.
3.4 Rumors of Riots by Korean residents in Japan
Previous research (Shinoda & Arai, 2022) has confirmed that such incidents occurred within Saitama Prefecture (Kumagaya, Honjo, Kamisato, Yorii, Fukaya, etc.), and it was found that similar events took place in Inzai City.
The diary entry for September 4, 1923, states: "On September 4th, at the request of the Kioroshi Police Station to be on alert for 'Korean residents in Japan' , fire brigade members were mobilized and sentries were posted at two locations in the district. The Kato residence was used as an office. We continued standing guard in shifts for about a week thereafter."
3.5 Damage Recorded in the Diary
The following damage was noted:
• Toppling of a stone lantern in the center of the back garden.
• Falling of tea jars, bottles, and cans.
• Clocks stopping.
• Overflowing of the fountain.
• Toppling of the stone pagoda of the guardian deity and other stone monuments.
The extent of damage to a single house and its surroundings suggests significant impact across Inzai City. The diary also mentions that "fires and power outages occurred in the Tokyo direction from September 1st to 3rd." The visibility of these fires suggests they may have reached Chiba Prefecture.
Furthermore, the description of "cracks of 3–9 cm in the ground and subsidences of 6–9 cm" suggests the occurrence of soil liquefaction. According to the Inzai City Liquefaction Hazard Map (Fig. 3), the susceptibility in Yoji-mura (Fig. 1, (2)) ranges from "somewhat high" to "extremely low." While the exact location of the residence is unknown, liquefaction is a strong possibility.
§4. Future Outlook
I intend to identify the specific earthquakes recorded in the diary (Table 2) by comparing them with the findings of Usami (2003).At the 42nd Conference of the Japanese Society for Historical Earthquakes (Toyooka Meeting), researchers suggested a physical approach to estimate the magnitude based on the damage descriptions while considering the context of government censorship of speech. I hope to incorporate these perspectives into my future research.
Acknowledgments
I would like to express my sincere gratitude to the staff of the Inzai City Kioroshi Koryu-no-Mori History Center (Fig. 1, (3)), and to Mr. Taishi Numano of the Science Research Club for his assistance with the diary investigation. I also received invaluable advice from alumni Mr. Yusuke Uemura (40th) and Mr. Haruka Shinoda (42nd), as well as current member Mr. Kouki Tokuda. I hereby record my thanks.