1911 Kikai Island earthquake

What Happened

On 15 June 1911, at 23:26 local time (14:26 UTC), a large earthquake struck the Ryukyu Islands in southern Japan. The epicentre lay near Kikai Island (喜界島, Kikai-jima), and the shock reached a surface-wave magnitude of Ms 8.1. The event is dated to the 44th year of the Meiji era, four years before the era gave way to Taishō.

At that hour most residents of the island chain were asleep. A magnitude of this size is capable of sustained ground shaking across a wide area, and an offshore epicentre in this part of the Ryukyus raises the further hazard of a sea wave reaching the coast within minutes.

Background

Kikai Island lies in the Ryukyu archipelago, the chain of islands that arcs from Kyushu south-west towards Taiwan. Administratively the island belonged to Oshima District (大島郡, Ōshima-gun), the district covering the Amami group. The Ryukyu arc sits where the Philippine Sea plate descends beneath the Eurasian plate, a setting that produces frequent and sometimes very large earthquakes along the island chain.

The earthquake occurred in the Meiji period (明治, Meiji, 1868–1912), an era of rapid institutional change in Japan. In the decades before 1911 the country had built a modern meteorological and seismological service, and the study of earthquakes had become an established scientific field in Japan — a consequence of the country's own experience of destructive shocks. By the 44th year of Meiji, an earthquake in a remote island district could be recorded instrumentally and reported within the emerging national network.

Why It Mattered

The 1911 Kikai Island earthquake ranks among the largest events recorded in the Ryukyu region, with a surface-wave magnitude of 8.1. Its epicentre near Kikai Island placed the strongest shaking directly on a populated island of the Amami group rather than in open sea far from settlement.

The date places the earthquake in the final year but one of the Meiji era. It belongs to the same generation of Japanese earthquakes that drove the development of seismic science and building practice, and it stands as a benchmark event for the Ryukyu arc in the instrumental record.

The Name in Japanese

The Japanese name is 喜界島地震. Its kana reading is きかいじまじしん, and its romaji is Kikai-jima Jishin.

Broken down character by character:

• 喜 — read here as き (ki). The character means "joy", "rejoice" or "delight". It is the first element of the island's name.
• 界 — read here as かい (kai). The character means "boundary", "world" or "sphere". Together, 喜界 (Kikai) is the name of the island; the two characters are used for their sound as much as their meaning.
• 島 — read here as じま (jima). The character means "island". This is the everyday word for island, normally read shima; after another element in a compound name it regularly voices to jima, which is why the island is Kikai-jima and not Kikai-shima.
• 地 — read here as じ (ji). The character means "earth" or "ground".
• 震 — read here as しん (shin). The character means "quake" or "shake".

The last two characters form the standard Japanese word for earthquake, 地震 (じしん, jishin), literally "earth-quake". The full name therefore reads as "the Kikai Island earthquake", following the common Japanese pattern of placing the place name before 地震.

Two pronunciation points are worth noting for learners. First, the island name is written 喜界島 but the reading of the first two characters, 喜界, is not the sum of their usual meanings — place names frequently work this way. Second, the voicing of 島 from shima to jima is a regular sound change in compounds, heard in names such as 鹿児島 (かごしま, Kagoshima) and 淡路島 (あわじしま, Awaji-shima). Recognising that pattern makes island names much easier to read aloud.

Key Figures

No individual person is associated with this earthquake in the record. The significant figures are institutional and geographic:

• Kikai Island (喜界島, Kikai-jima) — the island near the epicentre, in the Ryukyu Islands of southern Japan.
• Oshima District (大島郡, Ōshima-gun) — the district to which the affected area belonged.
• Emperor Meiji (明治天皇, Meiji Tennō) — the sovereign whose era name, Meiji, dates the event to the 44th year of that era.
• The Meiji era (明治, 1868–1912) — the period in which the earthquake occurred, and the last full era of the pre-Taishō state.