1968 Ebino earthquake

What Happened

On 21 February 1968, an earthquake struck the Ebino (えびの) district of Miyazaki Prefecture in southern Kyushu, close to the meeting point of three prefectures: Miyazaki, Kumamoto and Kagoshima. The shock had a moment magnitude of 6.2. The epicentre lay at roughly 32.066° north, 130.712° east.

The earthquake killed three people and injured forty-two. It struck during the Shōwa era (昭和, Shōwa, "bright harmony"), the reign period of the emperor Hirohito, in the forty-third year of that era — the year Western calendars number 1968.

Background

The Japanese archipelago sits where four tectonic plates meet, and the government has long maintained a dense seismic monitoring network. The 1968 Ebino earthquake belongs to the long record of damaging inland shocks on Kyushu, the southernmost of Japan's four main islands. Its epicentre lay in the mountainous interior near the Ebino plateau, a volcanic and seismically restless district.

The earthquake occurred in the same year that Japan's postwar economic boom was near its height. The country was in the middle of rapid industrialisation and urban growth, and public attention to disaster preparedness was rising. The 1964 Niigata earthquake and the 1968 Tokachi-oki earthquake had already pushed seismic safety into national debate. The Ebino shock, smaller than either, added to a growing body of evidence that inland faults, not only great offshore subduction earthquakes, posed a serious risk.

Why It Mattered

The Ebino earthquake is remembered as a moderate but deadly inland event. Its magnitude of 6.2 was modest by Japanese standards, yet it killed three people and injured forty-two. That ratio — a relatively small earthquake producing fatalities — illustrated a hard lesson: shallow inland earthquakes can be destructive even when their magnitude is unremarkable, because their energy is released close to populated areas.

The earthquake also drew attention to the volcanic and faulted interior of Kyushu. The Ebino area lies near the Kirishima volcanic group and the Ebino plateau, and the region has continued to experience seismic activity in the decades since. For seismologists, the 1968 event formed part of the record used to map active faults across Kyushu and to assess the hazard facing inland communities.

For the general public, the earthquake reinforced the case for earthquake-resistant construction and for rapid emergency response. The death toll of three was small compared with the great disasters of the twentieth century, but the injuries and damage made the event a local landmark. In the history of Japanese disaster preparedness, 1968 stands as a year of repeated seismic shocks, and Ebino is one of them.

The Name in Japanese

The Japanese name of the earthquake is えびの地震. Its kana reading is えびのじしん, and its romaji is Ebino jishin.

The name breaks down as follows:

• え — hiragana e. The first syllable of the place name Ebino.
• び — hiragana bi. The second syllable. Together, えびの (Ebino) is the name of the district in Miyazaki Prefecture where the earthquake struck. The place name is normally written in kanji as 海老野, literally "shrimp field", but the earthquake name uses hiragana for the place element.
• の — hiragana no. The third syllable of the place name, and also the possessive particle in Japanese, though here it belongs to the name itself.
• 地 — kanji read ji in this word. It means "ground" or "earth". It is the same character found in 地震 (じしん, jishin), the standard Japanese word for earthquake.
• 震 — kanji read shin in this word. It means "shake" or "tremor". Combined with 地, it forms 地震, "earthquake".

So えびの地震 reads literally as "the Ebino earthquake". The pattern — a place name followed by 地震 — is the standard way Japanese names earthquakes, as in 関東地震 (かんとうじしん, Kantō jishin, the Great Kantō earthquake) or 阪神・淡路大震災 (はんしん・あわじだいしんさい, Hanshin-Awaji daishinsai, the Great Hanshin-Awaji earthquake disaster). Learners will meet 地震 constantly in Japanese news and disaster reporting, and 震 (しん, shin) reappears in compounds such as 震度 (しんど, shindo, seismic intensity) and 余震 (よしん, yoshin, aftershock).

Note that the place element えびの is written in hiragana rather than kanji in this name. Japanese place names are sometimes rendered in kana in official and media usage, and earthquake names follow the form in which the place is conventionally written.

Key Figures

• Date: 21 February 1968
• Magnitude: 6.2 (moment magnitude)
• Epicentre: approximately 32.066° N, 130.712° E, near the border of Miyazaki, Kumamoto and Kagoshima Prefectures
• Deaths: 3
• Injuries: 42
• Era: Shōwa 43 (昭和43年), in the reign of Emperor Hirohito
• Location: Ebino, Miyazaki Prefecture, Kyushu, Japan