1948 Fukui earthquake

What Happened

At 4:13:31 p.m. on 28 June 1948, a magnitude 6.8 earthquake struck Fukui Prefecture in central Japan. The shaking was strongest in the city of Fukui, where it registered 6 on the Japan Meteorological Agency seismic intensity scale — a level that corresponds to the top of today's revised scale, 7. The hypocenter lay roughly 10 km north-northeast of Fukui, in what is now the Maruoka neighbourhood of Sakai City.

The timing was catastrophic. The quake hit in the late afternoon, when families were preparing meals and many people were indoors. Fires broke out across Fukui City almost immediately, and with water mains ruptured and roads blocked by collapsed buildings, they spread largely unchecked. Much of the city burned through the evening and into the night.

The earthquake also affected Ishikawa Prefecture, to the north of Fukui. The combined toll of the shaking and the subsequent fires made this one of the deadliest disasters of Japan's postwar period.

Background

The earthquake occurred in the 23rd year of the Shōwa era (昭和, Shōwa, "bright peace"), the reign period of Emperor Hirohito that ran from 1926 to 1989. In June 1948, Japan was three years into the postwar occupation and still rebuilding from the destruction of the Second World War. Fukui City had already been devastated by American air raids in 1945, and the reconstruction effort was ongoing when the earthquake struck.

Fukui Prefecture sits on the Sea of Japan coast, in a region known for seismic activity. The area's geology includes active fault systems, and the 1948 event was one of several major earthquakes to strike the region during the twentieth century. The combination of a shallow inland epicentre and densely built wooden housing created the conditions for both severe structural collapse and rapid fire spread.

The Japan Meteorological Agency seismic intensity scale (震度, shindo) measures how strongly the ground shakes at a given location, rather than the total energy released by the quake. In 1948 the scale ran to a maximum of 6. The intensity recorded in Fukui City that day was later reclassified as equivalent to 7 when the scale was revised, reflecting how extreme the local shaking had been.

Why It Mattered

The 1948 Fukui earthquake reshaped how Japan approached both earthquake science and disaster response. The severity of the damage in Fukui City — where the combination of ground failure and fire destroyed much of the urban core — demonstrated the limits of the seismic intensity scale then in use. The experience contributed to later revisions of the JMA scale, including the addition of intensity 7 as a distinct category for the most violent shaking.

The disaster also highlighted the danger of fire following an earthquake. In Fukui, as in Tokyo after the 1923 Great Kantō earthquake, the majority of destruction came not from the collapse of buildings alone but from the fires that followed. This pattern drove changes in urban planning, firefighting infrastructure, and building codes in earthquake-prone regions of Japan.

For Fukui itself, the earthquake arrived during an already difficult reconstruction period. The city had to rebuild a second time within a decade, and the disaster left a lasting mark on the prefecture's collective memory.

The Name in Japanese

The Japanese name for this event is 福井地震.

• Kana reading: ふくいじしん
• Romaji: Fukui jishin

Breaking the name down character by character:

福 (ふく, fuku) — "fortune," "good luck," "blessing." This is the same character used in words like 幸福 (こうふく, kōfuku, "happiness"). It is the first element of the place name Fukui.

井 (い, i) — "well," as in a water well. Together, 福井 (ふくい, Fukui) literally means "fortunate well," and it is the name of both the city and the prefecture. Place names of this type — combining a descriptive element with 井 — are common across Japan.

地 (じ, ji) — "ground," "earth," "land." This character appears in many geology and geography terms, such as 地図 (ちず, chizu, "map") and 地下 (ちか, chika, "underground").

震 (しん, shin) — "shake," "tremble," "quake." It appears in 地震 (じしん, jishin, "earthquake") and in 震度 (しんど, shindo), the seismic intensity scale mentioned above.

Put together, 地震 (じしん, jishin) is the standard Japanese word for "earthquake" — literally "ground shake." The full name 福井地震 therefore reads as "the Fukui earthquake," following the common Japanese convention of naming a disaster after the place where it struck.

Note that when 地 and 震 combine, the readings shift slightly: 地 is normally read ち (chi) on its own, but becomes じ (ji) in this compound. This kind of sound change, called rendaku (連濁, rendaku, "sequential voicing"), is extremely common in Japanese compound words and is worth watching for as you build vocabulary.

Key Figures

The earthquake struck the city of Fukui and the surrounding region of Fukui Prefecture, with effects also reaching Ishikawa Prefecture to the north. Its epicentre lay approximately 10 km north-northeast of Fukui, in the area that is today the Maruoka neighbourhood of Sakai City. The event took place during the Shōwa era, in the 23rd year of Emperor Hirohito's reign, and was recorded at intensity 6 on the Japan Meteorological Agency seismic intensity scale — a level equivalent to the current maximum of 7.