1891 Nōbi earthquake

What Happened

In the early morning of 28 October 1891, a major earthquake struck the Nōbi Plain, a broad lowland region of central Honshu. The shaking was felt across the provinces of Mino and Owari, which correspond to modern Gifu Prefecture and Aichi Prefecture. The event is known today as the 1891 Nōbi earthquake, and it remains the largest inland earthquake ever recorded in the Japanese archipelago.

The rupture broke the ground along a fault system that runs roughly northwest to southeast through the plain. The earthquake produced surface-wave magnitude 8.0 and moment magnitude 7.5. The most striking physical result was the appearance of many kilometres of visible fault scarps — fresh breaks in the earth's surface where one block of land had shifted vertically or horizontally against its neighbour. These breaks were not hidden underground; they cut across fields, roads and hillsides, leaving a scar that could be walked and measured.

Damage was widespread and the loss of life was significant. The earthquake struck in the Meiji period (明治, Meiji, 1868–1912), specifically in Meiji year 24, when Japan was still a largely rural society but was already several decades into a programme of rapid industrial and scientific modernisation. The timing placed the disaster at the centre of a national conversation about how a modern state should study and respond to natural hazards.

Background

The Nōbi Plain sits at the junction of several active fault systems. The earthquake of 1891 was generated by movement on what is now called the Nōbi fault zone, a set of connected faults that had accumulated strain over a long period. When the rupture occurred, the accumulated stress was released along a line long enough to produce surface breaks over a considerable distance.

The Meiji period was a time of institutional transformation. The old provincial system was being replaced by a modern prefectural administration, and scientific institutions modelled on Western examples were being founded. Seismology itself was a young discipline in Japan: the Japanese Seismological Society had been established in 1880, only eleven years before the earthquake, and foreign and Japanese scientists were actively working to understand why Japan experienced so many earthquakes.

The provinces of Mino and Owari had long been important agricultural and commercial regions. The plain was densely settled and intensively farmed, which meant that a large earthquake in this location would inevitably affect a substantial population and a great deal of infrastructure. The event therefore struck a region whose economic and social importance made its consequences a matter of national concern.

Why It mattered

The 1891 earthquake changed the study of earthquakes in Japan and beyond. The long, clearly visible fault scarps gave scientists an unusually direct view of what an earthquake actually does to the ground. Field investigations of these scarps led to an improved understanding of fault scarps themselves — the step-like features that earthquakes often generate where the surface is broken. Before this event, the connection between a specific fault and a specific earthquake was not something that could be observed so plainly.

The earthquake also arrived at a moment when Japan was advancing its scientific understanding in many fields and transforming into a more industrial nation. A disaster of this scale tested the young state's capacity to organise relief, survey damage and draw lessons. The event reinforced the argument that seismology was not an academic luxury but a practical necessity for a country built on unstable ground.

The rupture is remembered as the largest known inland earthquake in the Japanese archipelago. That distinction matters because it separates inland events, which occur on faults within the landmass, from the great offshore earthquakes that strike along subduction zones. The Nōbi earthquake demonstrated that the interior of the country could produce a rupture of extraordinary size, a fact that shaped later hazard planning and geological surveying.

The Name in Japanese

The Japanese name is 濃尾地震, read のうびじしん in kana and written Nōbi Jishin in romaji. The name is taken from the two historical provinces the earthquake struck: Mino (美濃) and Owari (尾張). The long vowel in Nōbi reflects the standard romanisation of the combined reading.

Breaking the name down character by character:

• 濃 — read のう (nō) in this word. The character means "thick", "dense" or "concentrated". It is the first element of the province name Mino (美濃), and it is the character that supplies the nō of Nōbi.
• 尾 — read び (bi) in this word. The character means "tail" or "end". It is the first element of the province name Owari (尾張), and it supplies the bi of Nōbi. The reading shifts from the character's more familiar o to bi because of the way the two province names were contracted together.
• 地 — read じ (ji) in this word. The character means "ground", "earth" or "land". It is the first element of the word for earthquake.
• 震 — read しん (shin) in this word. The character means "shake" or "tremble". Together, 地震 (じしん, jishin) means "earthquake".

So the full name is a compound of two place names plus the ordinary word for earthquake. The same event is also called 濃尾大地震 (のうびだいじしん, Nōbi Daijishin), adding 大 (だい, dai, "great"), and 岐阜大地震 (ぎふだいじしん, Gifu Daijishin), after Gifu. English-language sources sometimes render it as the Mino–Owari earthquake, using the same two province names in their separate forms.

Key Figures

The facts available for this event do not name individual scientists, officials or other persons associated with the earthquake or its investigation. The historical record of the 1891 Nōbi earthquake is therefore presented here through its date, its location, its measured magnitudes and its physical effects on the ground, rather than through a cast of named individuals.