earth science

Namazu

Namazu is a earth science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Namazu rather than just read about it. In short: In Japanese mythology, the Namazu (鯰) or Ōnamazu (大鯰) is a giant underground catfish who causes earthquakes. The creature lives under the islands of Japan and is guarded by the god Takemikazuchi enshrined at Kashima, who restrains the catfish with a stone.

Key takeaways

Namazu belongs to earth science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Namazu to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Namazu from memory before moving on to harder problems.

Reference excerpt

In Japanese mythology, the Namazu (鯰) or Ōnamazu (大鯰) is a giant underground catfish who causes earthquakes. The creature lives under the islands of Japan and is guarded by the god Takemikazuchi enshrined at Kashima, who restrains the catfish with a stone. When the Kashima-god lets his guard fall, Namazu thrashes about, causing violent earthquakes.

Myth The legend or myth in Japan is that a gigantic namazu (catfish) lives inside or beneath the earth (or in the mud) which causes earthquakes. The association of the namazu with earthquake seems to have first occurred in the area around Lake Biwa, around the 16th century. The namazu had been depicted in the Ōtsu-e ("pictures from the city of Otsu") which were manufactured in that area. This earthquake-causing creature became associated with the deity and "foundation stone" in Kashima, Ibaraki. According to myth, the god Takemikazuchi enshrined at Kashima restrains the catfish underneath a stone (要石, kaname-ishi, perhaps "foundation stone" but maybe more aptly "cap stone"). When the Kashima-god lets his guard fall, Namazu thrashes about, causing violent earthquakes.

Explanation Widespread connections between catfish and earthquakes in Japan were not present until the late 17th century, and only rose to popularity as symbolically causing or predicting earthquakes during the 19th century. Prior to the 1855 Edo earthquake, an eel fisherman reportedly spotted unusually active catfish in a river, which he took as a predictor of an earthquake. Later that night, the earthquake struck. The anecdote, recorded in an 1856 chronicle of journalistic reporting on the earthquake, is the earliest known claim that catfish can naturally predict earthquakes. In the 1930s, Japanese seismologists Shinkishi Hatai and Noboru Abe demonstrated that catfish in aquaria showed increased agitation several hours before earthquakes occurred, and were able to predict quakes with 80% accuracy.

History

Namazu-e Namazu-e (鯰絵; "catfish prints") were a known item in the 19th century, and these broadsides were printed in great quantity following the 1855 earthquake near Edo (modern day Tokyo), one of the Ansei great earthquakes. These namazu-e woodblock-prints encompass a large variety of scenes, typically depicting the god subduing the earthquake-causing catfish under a sword or the kanameishi stone. The creature is sometimes referred to as just the "earthquake fish" (jishin-no-uo), and despite the text calling it a catfish, the illustration may be that of a dragon-serpent. Even though the Namazu was held responsible for the disaster, it was also ironically hailed as a yonaoshi daimyōjin (god of "world rectification"), that is to say, a sort of an "avenger of social injustice" which expressed the public's political sentiment at the time. The rich had hoarded their wealth but these were largely disgorged due to the earthquake, and redistributed to the world at large: such is the symbolism of the large gold coins (koban, etc.) scattered by the earthquake depicted in the pictures. A large amount of money went into the rebuilding effort, and the job opportunities resulted in a redistribution of wealth. One picture is printed with a jingle with the refrain "yo-naoshi, yo-naoshi, tate-naoshi" (literally "world-fixing, world-fixing, re-building", which explicitly makes this connection.

Modern use

Catfish are depicted on pictures of emergency earthquake preparedness activities in Japan. For example, the Earthquake Early Warning (EEW) logo by the Japan Meteorological Agency utilizes pictures of the catfish on devices capable of issuing an early warning. The popular earthquake early warning mobile application Yurekuru Call also has a catfish as their icon. The Open-Source Seismic Hazard Analysis (OpenSHA) software platform has used a catfish logo since its publication to an SVN repository circa 2008. The Pokémon Whiscash, named "Namazun" in Japan, resembles a catfish and has "Earthquake" as its signature move. An episode of the Pokémon anime featuring Whiscash was scheduled to air on November 4, 2004, but was skipped over after the 2004 Chūetsu earthquake. The Namazu was featured in the episode of River Monsters, "Cold-Blooded Horror". Namazu appears in a crossover comic book featuring Stan Sakai's Usagi Yojimbo and IDW's Teenage Mutant Ninja Turtles. The Namazu are a race that resemble short, chubby, bipedal catfish in Final Fantasy XIV: Stormblood. The player can undertake crafting and gathering quests for them, or fight Namazu that have forsaken "civilized" garments and have taken up banditry. In S1:E7 of Dragon Ball GT, the character Zoonama appears as a giant catfish that wiggles his whiskers when detecting earthquakes, and repeats the word "Namazu" in his speech. The myth of Namazu and a scroll of namazu-e is referenced throughout the 2022 Japanese animated fantasy film of Makoto Shinkai, Suzume.

Gallery

Explanatory notes

References Citations

Bibliography

External links

Namazu-e: Earthquake catfish prints from the period after the Great Ansei Earthquake struck the city of Edo (now Tokyo) in November 1855.

Illustrations

Worked examples

Example 1 — a first encounter with Namazu

Start with the simplest possible case. Write down what Namazu claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In earth science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Namazu before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Namazu ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Namazu

In research: Namazu appears in earth science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Namazu in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Namazu is common in secondary-school and first-year university syllabi. It links to neighbouring topics Earthquake myths, Fish in religion, Legendary fish, so understanding it makes those chapters shorter.
In everyday life: Look for Namazu outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Namazu in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Namazu means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Namazu out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Namazu in simple terms?

Why does Namazu matter?

Because it connects several earth science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Namazu?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Namazu.