Postscript (Postscript placed in the edition printed in 1990)

As a researcher in seismology, I am naturally interested in major earthquakes and earthquake damage in the past, both at home and abroad. I have been taking notes of newspaper articles and what I have heard from foreign researchers, though not in an organized way. However, as I have been fully occupied with the study of seismology, I have not had spare time to study and research past earthquakes abroad, except those urgently required by my study.

Several years ago, when I felt it was necessary to make a table of destructive earthquakes of the world, I was disappointed by the foreign material on earthquakes. None of the rudimentary tables in certain books on earthquakes, big volume encyclopedias or almanacs reached my expectations. Some of them seem to have selected earthquakes on a random basis. They did not tabulate several well-known major earthquakes, while tabulating some insignificant earthquakes.

Several long-established catalogs exist among the catalogs of destructive and well-known earthquakes worldwide since recorded history, such as Mallet (1852-1854), Milne (1911) and Sieberg (1932). The catalog of Ganse and Nelson (1982) covers recent earthquakes. The Ganse and Nelson catalog looks into 159 references and selects about 2,500 earthquakes based on certain criteria, listing them with latitude and longitude of the epicenter. It was presumably a big task, regardless of the accuracy of the data.
However, even this catalog omits the well-known Quetta Earthquake in Pakistan in 1935 and the Khait Earthquake in the Soviet Union in 1949, and the Assam Earthquake in India in 1987 is also missing. No earthquakes that occurred around 1898 are included in this catalog, and the Yaktat Bay Earthquake is also excluded. And I can find exactly the same lines arranged redundantly in this catalog. It occasionally happens that a part of the data is mistakenly deleted or duplicated while being processed by computer. Including additional information on the latest earthquakes, this catalog went on sale on magnetic tape file. The earthquakes missing in the previous edition were added to the magnetic file, but most of the mistakes were left uncorrected. With regard to the additions, for example, the magnetic file set the number of deaths in the Urakawa Offshore Earthquake in 1982 at 100 (the correct figure is zero). (It is unlikely that the number of casualties was correctly placed in the casualty column only for this earthquake, because the number of fatalities was mistakenly placed in the casualty column of other earthquakes.) Also, Guinea in Africa was mistakenly entered as New Guinea in this catalog.

Let me point out some incorrect data in existing catalogs. Some articles report that the Hokkaido Earthquake of Dec. 30, 1730 caused total fatalities of 137,000 (for instance, Sieberg (1932), Bath (1979)). Knowledge of the history and geography of Japan is sufficient to know that the data are incorrect. How was this big illusionary earthquake created?

I presume that the Genroku Kanto Earthquake of Dec. 31, 1703 (Dec. 30, universal time) that considerably damaged Edo was erroneously entered or typeset as the Hokkaido Offshore Earthquake. Someone presumably entered 1730 for 1703 and Ezo (or Yezo) for Edo (or Yedo). Ezo as a location name does not exist on a map of Japan. Knowing that Hokkaido used to be called Ezo, someone rewrote Ezo as Hokkaido because it was hardly possible to know where Ezo was.

A little after the Hokkaido Offshore Earthquake, an earthquake accompanied by tidal waves hit Kamchatskaya on Oct. 17, 1737. Both "Earthquakes" written by Prof. Matsuzawa in 1933 and "Outline of Seismology" written by Prof. Honda in 1943 placed an article reporting that this earthquake killed 30,000 people. This article is a reprint from the "Chronological Table of Major Earthquakes Worldwide" in the "Chronological Scientific Tables," which originally came from Milne (1911).
However, the Kamchatskaya Earthquake in the Milne table does not present a death toll; instead, the Calcutta Earthquake placed one line above the Kamchatskaya Earthquake has total fatalities of 300,000. It is presumed that someone mistakenly read one line above and added one more digit to the original figure.

Unaware of the mistake, I have been suspicious of the report of 30,000 deaths. I had an opportunity of meeting Dr. Fedotov, the president of the Kamchatskaya Volcano Research Laboratory, and asked him about the number of deaths in the Kamchatskaya Earthquake. Judging from the population at that time, he said that the number of deaths was about 100. I am also suspicious of the report that the Calcutta Earthquake of Oct. 11, 1737 killed 300,000 people, and I found an article reporting that high water accompanied by a cyclone hit Calcutta on Oct. 7 in the same year, killing 300,000 people. An earthquake may have hit Calcutta, but it is highly likely that the fatalities caused by the high water have been mixed up as those caused by the earthquake.

There are supposedly not very many serious mistakes such as these, but in the references I used, I found a quite a number of earthquakes with different years, months and days that are considered to be the same earthquakes. However, it is not unusual that big earthquakes hit the same area successively; therefore, it is not wise to delete them without careful consideration. It is necessary to look into original historical sources to confirm mistakes before deleting them.

The number of deaths is also a controversial issue. Even recently, only few countries, including Japan, publish the accurate number of deaths after a big earthquake. It is sometimes difficult to obtain the correct death toll because several figures are often left for the record, and the difference in data is sometimes as big as 10 times.
Suspicions have arisen endlessly once I started becoming suspicious of the credibility of articles in references including the death toll, but I have neither the knowledge nor time to resolve these suspicions. Under these circumstances, it is hardly possible to make an accurate catalog that can tolerate criticism from learned people.

When big earthquakes like the Armenia Earthquake occur, I have to answer questions about past earthquakes in the same district, and I receive inquiries about earthquakes in countries that I least expect due to the increase in the number of Japanese going abroad. It is helpful to make a file of destructive earthquakes worldwide to enable data search as the occasion demands although it is unrealistic to aim at perfection. First, I thought that modifying the Ganse and Nelson catalog would satisfy these needs. I found, however, that it has many problems, and I decided to make a file myself by researching the references of the Earthquake Research Institute.
This job alone took more time than expected, and the day of my involuntary retirement arrived. Just before retirement, I printed the semi-finished file as a provisional edition and distributed it among major research agencies in Japan. I have been revising the file thereafter, and I have corrected mistakes when I noticed them. I have added more than 2,000 pieces of information and about 500 earthquakes to the file.

There may still be some mistakes and omissions, and I have reprinted articles of references as they are even if they seemed somewhat doubtful. I think that the file may be of help for study on earthquakes and for disaster prevention, and I changed the format of the table a little for ease of printing. The file has been put on one 1MB floppy diskette that is available upon request. I would very much appreciate any comments because I wish to continue revising and adding.

This table is based on the file I made while working for the Earthquake Research Institute. Engineering official Ms. Ikuko Kato helped me with data entry, data comparison, checking and modification. She conducted laborious research on the names of countries, cities and areas. I also received useful information from many colleagues including Prof. Katsumasa Abe, to whom I offer my sincere thanks.


Tokuji Utsu
October 10, 1989