The was one of the most destructive seismic events in Japanese history.
The 8.5
magnitude
Magnitude may refer to:
Mathematics
*Euclidean vector, a quantity defined by both its magnitude and its direction
*Magnitude (mathematics), the relative size of an object
*Norm (mathematics), a term for the size or length of a vector
*Order of ...
earthquake occurred at 19:32 (local time) on June 15, 1896, approximately off the coast of
Iwate Prefecture
is a prefecture of Japan located in the Tōhoku region of Honshu. It is the second-largest Japanese prefecture at , with a population of 1,210,534 (as of October 1, 2020). Iwate Prefecture borders Aomori Prefecture to the north, Akita Prefectur ...
,
Honshu
, historically called , is the largest and most populous island of Japan. It is located south of Hokkaidō across the Tsugaru Strait, north of Shikoku across the Inland Sea, and northeast of Kyūshū across the Kanmon Straits. The island separ ...
. It resulted in two
tsunami
A tsunami ( ; from ja, 津波, lit=harbour wave, ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and other underwater explo ...
waves which destroyed about 9,000 homes and caused at least 22,000 deaths.
The waves reached a then-record height of ; this would remain the highest on record until waves from the
2011 Tōhoku earthquake exceeded that height by more than .
From the tsunami records the estimated
tsunami's magnitude is (M
t = 8.2), much greater than expected for the seismic magnitude estimated from the observed seismic intensity (=7.2).
This earthquake is now regarded as being part of a distinct class of seismic events, the
tsunami earthquake
In seismology, a tsunami earthquake is an earthquake which triggers a tsunami of significantly greater magnitude, as measured by shorter-period seismic waves. The term was introduced by Japanese seismologist Hiroo Kanamori in 1972. Such events a ...
.
Geology
![Meiji-Sanriku earthquake 02](https://upload.wikimedia.org/wikipedia/commons/7/7d/Meiji-Sanriku_earthquake_02.jpg)
The epicenter lies just to the west of the
Japan Trench
The Japan Trench is an oceanic trench part of the Pacific Ring of Fire off northeast Japan. It extends from the Kuril Islands to the northern end of the Izu Islands, and is at its deepest. It links the Kuril–Kamchatka Trench to the north and t ...
, the surface expression of the west-dipping
subduction
Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, the ...
zone. The trench forms part of the
convergent boundary
A convergent boundary (also known as a destructive boundary) is an area on Earth where two or more Plate tectonics, lithospheric plates collide. One plate eventually slides beneath the other, a process known as subduction. The subduction zone can ...
between the
Pacific
The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...
and
Eurasian
Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily in the Northern and Eastern Hemispheres, it spans from the British Isles and the Iberian Peninsula in the west to the Japanese archipelago ...
plates.
Magnitude
The unusual disparity between the magnitude of the earthquake and the subsequent tsunami may be due to a combination of factors:
# the tsunami was caused by a slope failure triggered by the earthquake
# the rupture velocity was unusually low
Scientists believe the effect of subducted sediment beneath the
accretionary wedge
An accretionary wedge or accretionary prism forms from sediments accreted onto the non-subducting tectonic plate at a convergent plate boundary. Most of the material in the accretionary wedge consists of marine sediments scraped off from the do ...
was responsible for a slow rupture velocity. The effects of a 20° dipping fault along the top of the subducting plate was found to match both the observed seismic response and tsunami, but required a displacement of 10.4 m.
The displacement was reduced to a more reasonable value after the extra uplift caused by the deformation of sediments in the wedge and a shallower fault dip of 10° was considered. This revised fault model gave a
magnitude
Magnitude may refer to:
Mathematics
*Euclidean vector, a quantity defined by both its magnitude and its direction
*Magnitude (mathematics), the relative size of an object
*Norm (mathematics), a term for the size or length of a vector
*Order of ...
of =8.0–8.1. A figure much closer to the estimated actual tsunami magnitude.
A magnitude of 8.5 on the
moment magnitude scale
The moment magnitude scale (MMS; denoted explicitly with or Mw, and generally implied with use of a single M for magnitude) is a measure of an earthquake's magnitude ("size" or strength) based on its seismic moment. It was defined in a 1979 pape ...
has also been estimated for this event.
Tsunami
On the evening of June 15, 1896, communities along the
Sanriku coast
The is a coastal region on the Pacific Ocean, extending from southern Aomori Prefecture, through Iwate Prefecture and northern Miyagi Prefecture in northeastern Honshū, which is Japan's main island. The name comes from the historical region of S ...
in northern Japan were celebrating a
Shinto
Shinto () is a religion from Japan. Classified as an East Asian religion by scholars of religion, its practitioners often regard it as Japan's indigenous religion and as a nature religion. Scholars sometimes call its practitioners ''Shintois ...
holiday and the return of soldiers from the
First Sino-Japanese War
The First Sino-Japanese War (25 July 1894 – 17 April 1895) was a conflict between China and Japan primarily over influence in Korea. After more than six months of unbroken successes by Japanese land and naval forces and the loss of the po ...
. After a small earthquake, there was little concern because it was so weak and many small tremors had also been felt in the previous few months. However, 35 minutes later the first tsunami wave struck the coast, followed by a second a few minutes later.
[Corkill, Edan,]
Heights of survival
, ''Japan Times
''The Japan Times'' is Japan's largest and oldest English-language daily newspaper. It is published by , a subsidiary of News2u Holdings, Inc.. It is headquartered in the in Kioicho, Chiyoda, Tokyo.
History
''The Japan Times'' was launched by ...
'', 12 June 2011, pp. 9–10. The damage was particularly severe because the tsunamis coincided with high tides. Most deaths occurred in
Iwate and
Miyagi Miyagi may refer to:
Places
* Miyagi Prefecture, one of the 47 major divisions of Japan
* Miyagi, Gunma, a village in Japan, merged into Maebashi in 2004
*Miyagi District, Miyagi, a district in Miyagi Prefecture, Japan
Other uses
* Miyagi (surna ...
although casualties were also recorded from
Aomori
is the capital city of Aomori Prefecture, in the Tōhoku region of Japan. , the city had an estimated population of 278,964 in 136,457 households, and a population density of 340 people per square kilometer spread over the city's total area of ...
and
Hokkaido
is Japan's second largest island and comprises the largest and northernmost prefecture, making up its own region. The Tsugaru Strait separates Hokkaidō from Honshu; the two islands are connected by the undersea railway Seikan Tunnel.
The la ...
.
The power of the tsunami was great: large numbers of victims were found with broken bodies or missing limbs.
As was their normal practise each evening, the local fishing fleets were all at sea when the tsunamis struck. In the deepwater, the wave went unnoticed. Only when they returned the next morning did they discover the debris and bodies.
Wave heights of up to were also measured in
Hawaii
Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only stat ...
. They destroyed wharves and swept several houses away.
Legacy
Preventive coastal measures were not implemented until after another tsunami struck in 1933. Due to higher levels of tsunami awareness, fewer casualties were recorded following the
Sanriku earthquake.
Nevertheless, the
earthquake of 11 March 2011 caused a huge tsunami that resulted in thousands of deaths across the same region and the
nuclear disaster at Fukushima.
See also
*
869 Sanriku earthquake
__NOTOC__
Year 869 ( DCCCLXIX) was a common year starting on Saturday (link will display the full calendar) of the Julian calendar.
Events
By place
Byzantine Empire
* Summer – Emperor Basil I allies with the Frankish emperor L ...
*
1933 Sanriku earthquake
The occurred on the Sanriku coast of the Tōhoku region of Honshū, Japan on March 2 with a moment magnitude of 8.4. The associated tsunami caused widespread devastation.
Earthquake
The epicenter was located offshore, east of the city of Kama ...
*
2011 Tōhoku earthquake and tsunami
The occurred at 14:46 JST (05:46 UTC) on 11 March. The magnitude 9.0–9.1 (M) undersea megathrust earthquake had an epicenter in the Pacific Ocean, east of the Oshika Peninsula of the Tōhoku region, and lasted approximately six minutes ...
*
List of earthquakes in Japan
This is a list of earthquakes in Japan with either a magnitude greater than or equal to 7.0 or which caused significant damage or casualties. As indicated below, magnitude is measured on the Richter magnitude scale (''ML'') or the moment magnitud ...
*
List of historical earthquakes
Historical earthquakes is a list of significant earthquakes known to have occurred prior to the beginning of the 20th century. As the events listed here occurred before routine Seismometer, instrumental recordings, they rely mainly on the analys ...
*
Seismicity of the Sanriku coast
The seismicity of the Sanriku coast identifies and describes the seismic activity of an area of Japan. Seismicity refers to the frequency, type and size of earthquakes experienced over a period of time. The is a descriptive term referring to th ...
References
{{Earthquakes in the 1890s (decade)
Megathrust earthquakes in Japan
Tsunamis in Japan
Meiji-Sanriku earthquake
Meiji-Sanriku earthquake
Meiji-Sanriku earthquake
Earthquakes in the Empire of Japan
June 1896 events
Tsunami earthquakes
Earthquakes of the Meiji period
1896 disasters in Japan