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🚗 | [Gunma] Manza Highway-Mt.


[Gunma] Manza Highway ~Mt.

If you write the contents roughly
I would like to run the straight road that leads to Onioshidashi in front of it at dawn.

Road Overview A toll road from Tsumagoi, which is famous for highland vegetable cabbage cultivation, to Manza Onsen.From Karuizawa (Mine no Chaya) to Tsumagoi... → Continue reading

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Wikipedia related words

If there is no explanation, there is no corresponding item on Wikipedia.

Linear (route)

linear(Senkei,alignment) Is道路,TrainThe shape of the route such as.That is, what is the shape of the flat line?Straight linecurveIs a combination of, uphill, downhill, etc.SlopeIt shows how is configured.


When a road or railroad connects a starting point (starting point) to a destination (ending point), it is not common that the shape is composed only of straight lines or that they are all flat.If there is an obstacle on the way, it is necessary to insert a curve in the line to avoid it, and if there is a height difference between the start point and the end point, it is necessary to provide a slope on the line.The shape of such a line is called linear.

Linear indicates a combination of planar straight lines and curvesHorizontal alignment, Shows the slope along the routeAlignmentIn addition, it is provided so that the vehicle can run smoothly in the curved section.One-sided gradient / KantAnd so on, these individuallyAlignment elementIt is called.In general, horizontal alignment is mainly composed of straight lines and loose curves.Longitudinal slopeIs near flatLinear is goodOn the contrary, routes with many sharp curves and steep slopes are calledBad alignmentIs called.The quality of the alignment affects the running performance of the vehicle, and a route with a good alignment can comfortably run at high speed.

In addition to railroads and roads, linearRiverIt is also used to indicate the shape of.

Horizontal alignment

Straight line and radius of curvature / curvature

Alignment is a linear element that indicates the planar shape of a line.The basics of horizontal alignment are straight lines and arc curves, both of which are arcs.radiusRShown with.The smaller the radius R, the steeper the curve, and the straight lineR= ∞ (infinity).Also, the horizontal alignment iscurvaturekCan also be indicated by the reciprocal of the radiusk=1/RThere is a relationship of.Therefore, the larger the curvature, the sharper the curve, and if the straight line is indicated by the curvature,k= 0.

When the traveling vehicle approaches the curved section of the route, the vehicleCentrifugal forceWorks.The centrifugal force at this time can be expressed by the following equation.


  • F - Centrifugal force
  • m --Vehicle mass
  • v --Vehicle running speed
  • R - curvature radius
  • k --Curvature


From this, it can be seen that the centrifugal force increases as the traveling speed of the vehicle increases, and increases as the radius of curvature decreases.When the centrifugal force becomes excessiveRide comfortIn addition to damaging the vehicle, the vehicle capsizes, derails, deviates from the road, etc.ACCIDENTCauses.Therefore, in order for the vehicle to comfortably travel at high speed, it is necessary to increase the radius of curvature (decrease the curvature).If it is unavoidable to have a small radius of curvature, a speed limit is set for the traveling vehicle.

Relaxation curve

As mentioned above, the basics of horizontal alignment are straight lines and arc curves, and the arc curve is the radius of curvature (curvature radius) in the curve section.curvature) Is constant.However, when directly shifting from a straight section to a curved section, the traveling vehicle suddenly changes.handleIt adversely affects ride comfort and safety, such as being required to operate and suddenly applying a large centrifugal force.In particular, a sudden transition to a sharp curve with a small radius of curvature has a large effect.

So a straight line (radius of curvature)R = ∞ / Curvaturek = 0) May insert a curve that gradually changes to the curvature of a given arc curve.Relaxation curveCalled.The transition curve improves driving operation and riding comfort, and will be described later.One-sided gradient / KantTo change smoothly (Kant's diminishing)[1]) Can be done.Further, the transition curve is inserted not only when connecting a straight line and a curve but also when connecting arc curves having different radii of curvature.In railways, there is no arc curve part and only the transition curve part.Total transition curveMay be used.

In the case of roads, the gradual decrease in curvature is constant, but in the case of railways, it gradually decreases linearly.Straight line diminishingAnd gradually decrease in a curveCurve diminishingThere is.In the case of linear diminishing, the curvature cannot be differentiated at the start and end points of the transition curve, but in the case of curving diminishing, the start and end points of the transition curve become differentiable, so it is used in high-speed railways (Shinkansen, etc.).

Generally, the following curve is used as the transition curve.

  • Clothoid curve Straight line diminishing (perfect straight line)
    • It is a curve in which the curvature changes at a constant rate.
    • At a constant speed while driving at a constant speedhandleCorresponds to the locus when operating.
    • It is used as a transition curve for roads.
    • In the case of railways, the calculation for maintenance is relatively difficult.Labor saving trajectoryIt is often adopted in the case of.
  • 3rd order curve (3rd order parabola) Straight line diminishing (not a perfect straight line)
    • Alignment curve used in railways[2]..Because the calculation for maintenance is easier than the clothoid curveBallast orbitThen this is often adopted.
  • Sine half-wavelength diminishing curve Curve diminishing
    • Used on railroads[2],JapanThen.ShinkansenIt is used for sections that travel at 120 km / h or more.
  • McConnell curve



Example of maximum design speed and superelevation
Design speed

(km / h)

Gradient limit (%)
Specified valueSpecial value
Road structure ordinanceAn example of a Japanese ordinary road by.The special value is the upper limit when it is unavoidable.

When a line connects two points with different heights, the line between them isSlopeWill have.Especially to distinguish this gradient from the one-sided gradient described later.Longitudinal slopeSometimes called.

The degree of gradient is generallypercentage or Per milleIs expressed using.The slope of the road is generally a percentage, and if it is 5%, it is a slope with a height difference of 100 m when traveling 5 m horizontally.On the other hand, for railways with a smaller slope than roads, it is shown as a fraction, and for 10 per mil, the slope has a height difference of 1000 m when traveling 10 m horizontally.Also, especially that the gradient is 0, that is, flat.LevelCalled (level).

Large gradients affect the speed of the traveling vehicle.A steep uphill puts a burden on the acceleration of the vehicle, and a steep downhill makes the braking effect worse, so it is not suitable for high-speed driving.Therefore, the maximum value of the gradient is generally set according to the design speed of the route.Further, as in the case of planar alignment, a speed limit may be set when a steep slope is unavoidably set.

The table on the right shows examples of Japanese roads.Road structure ordinanceIndicates the "limit value of the longitudinal gradient with respect to the design speed" defined by.It can be seen that the higher the design speed, the stricter the limit value is set for the longitudinal gradient.

Longitudinal curve / vertical curve

Difference in visibility depending on the presence or absence of a vertical curve
Vertical curve less.gif
Vertical curve.gif
Top-If there is no vertical curve.
Bottom-If there is a vertical curve.

At a point where the slope changes, if the slope is suddenly changed at one point, a "break" will occur on the route, which is not preferable, such as hindering the running performance or contacting the bottom of the vehicle with the road surface.Therefore, at the change point of the gradient, a curve is inserted in the longitudinal direction, and the gradient is gradually changed.This curveLongitudinal curve, Or from English notationVertical curve (vertical curve), Especially in railwaysVertical curveCall[4]..The vertical curve is a quadratic curve (parabola) Is used, but since it can be approximated by an arc, its size is expressed using a radius.

As shown in the right figure, the vertical curve also has the effect of ensuring the visibility of the vehicle.The upper part of the figure on the right is the case where there is no vertical curve, and the vehicle running in front of the gradient change point cannot see the vehicle running ahead due to the blind spot caused by the gradient change point.On the other hand, if a vertical curve is inserted as shown in the figure below, the blind spot becomes smaller and the vehicle in front can be visually recognized.The distance at which visibility can be ensured from such a linear stateViewing distanceCall it (Shikyo).Since it is necessary to take a large viewing distance on a route with a high design speed, it is required to take a large radius of the longitudinal curve.

One-sided gradient / Kant

Slope given to the curved part

Horizontal alignmentAs described above, a centrifugal force that tries to push the vehicle out of the curve acts on the vehicle traveling on the curved portion.Excessive centrifugal force hinders riding comfort and adversely affects stable driving.

Therefore, by lowering the inside of the curved portion or raising the outside of the curved portion to give the vehicle an inclination in the direction opposite to the centrifugal force, the traveling of the curved portion of the vehicle is made comfortable and smooth.On the road, this is because the entire road surface is tilted inward of the curve.One-sided gradient(Katakoubai)bank (bank).The one-sided gradient is expressed as a percentage (percentage) like the longitudinal gradient.On the other hand, in railways, the same effect can be obtained by making a height difference between the rails inside and outside the curve.thisCant (cant), Which is indicated by the height difference of the rail (millimeter in Japan).


The roles of one-sided gradient and Kant are as follows.

Work to reduce the force due to centrifugal force
When centrifugal force acts on a vehicle, a force that tries to cause skidding between the tire and the road surface acts on the automobile, and a lateral pressure that pushes the rail by the wheel acts on the railroad vehicle.When these become excessive, automobiles begin to skid, and railcars can derail their wheels over the rails.On the other hand, the one-sided gradient and the cant exert a force in the opposite direction to the centrifugal force due to the inclination, and have a function of reducing these effects.
Work to prevent falls and capsizes
Centrifugal force acts on the center of gravity of the vehicle.Therefore, in a vehicle having a high center of gravity, a rotational force (moment) that tries to overturn or capsize acts due to centrifugal force.On the other hand, the one-sided gradient and the cant have the effect of moving the position of the center of gravity of the vehicle to the inside of the curved portion, and give a moment in the opposite direction.This has the effect of reducing the rotational force of overturning and overturning.
Work to improve ride comfort
Centrifugal force acts not only on the vehicle but also on passengers and passengers in the vehicle.Excessive centrifugal force also affects ride comfort, but proper one-sided slopes and cants also improve ride comfort.For example, if the centrifugal force and the rotational force due to the one-sided gradient / cant match, the person in the car does not feel the centrifugal force.If you are careful, you may notice a change in vertical acceleration (change in gravity you feel), but the effect on riding comfort is much smaller than when you receive horizontal acceleration.

Water gradient (road)

One-sided gradients and cants are basically provided in curved sections where centrifugal force acts, and theoretically it is not necessary to provide them in straight sections where the curvature is 0.However, if the slope of the road surface is horizontal on the road, water tends to collect on the road surface in rainy weather and drainage is not good. Therefore, a slope (about 1.5% to 2%) is provided so that water can flow even in a straight section. ing.

Also (on the left side),Two-wheeled VehiclesIt is this water gradient that tends to reduce the right side of the tire.

Synthetic slope (road)

Longitudinal slopeThe gradient that combines and one-sided gradient (crossing gradient) is called the combined gradient, and is the steepest slope of the road surface.A composite slope occurs when there is a plane curve in a section of the road with a vertical slope.Here, the automobile receives gradient resistance and curve resistance at the same time, and the resistance becomes larger than usual.Especially when the slope is steep and the radius of the curve is small, driving danger is likely to occur.

Its size is


  • S : Composite gradient (%)
  • i : One-sided gradient (%)
  • j : Longitudinal gradient (%)

Obtained at.


How to represent the station
Description example距離
(From the starting point)
No.22 + 2.0442.0 m道路
STA.5+12.0512.0 mhighway
12k57312,573 mTrain

Other terms related to linearity are outlined.

Widening element
In the curved section of the roadInner ring differenceA linear element that widens the inside of the curved part in order to absorb the influence of and secure the viewing distance.
A linear element that facilitates curved running of railway vehicles by slightly moving the rails inside the curved section to widen the rail spacing in the curved section of the railway.
Sokuten and kilometers
It shows the distance from the starting point to the ending point along the route.
It is installed on the road.In Japan, every 20 metersNo.In addition to assigning (number) in order, every 100 meters on the highwaySta.(Station) may be used.When indicating a position other than the station, the distance from the station in front is used.MetersAdd in units,Sokuten + ○○It is shown in the form of.
About a kilo
The distance from the starting point by railKilometersShown in units.After the distancekIs added, and if there is a fraction less than a kilometer, a number in meters is added after k.on the other hand,Imperial imperialIn countries where the unit system of is used, "mileage" is used, and even in Japan, it was based on miles before the transition to the metric system.


[How to use footnotes]
  1. ^ Kant's diminishing --Track Maintenance Wiki (Tuesday, August 2015, 8 11:09 version) Retrieved August 54, 2018
  2. ^ a b "Railway Engineering" pp.51-52
  3. ^ Highway Curves and Test Track Design American Academy of Sciences KA Stonex, William A. McConnell 1957
  4. ^ "Railway Engineering" p.54


  • "Explanation and Operation of Road Structure Ordinance" edited by Nippon Road Association (revised edition), February 2004.ISBN 978-4-88950122-3. NCID BA66671474. 
  • Kamiura, Masaki, Onoda, Shigeru, Sucho, Makoto "Railway Engineering" (1st edition) Morikita Publishing, 2000.ISBN 978-4-62748471-9. 

Related item

Mt. Asamayama

Mt. Asamayama(Asayama)NaganoKitasaku DistrictKaruizawaas well as the MiyotaGunmaAgatsumaTsumagoi VillageOn the border withAndesiteQualityelevation2,568Meter (m) OfStratovolcano..The mountain bodyconeIn the form ofcalderaIs also formed and livelyactive volcanoKnown as.


In the surrounding area for hundreds of thousands of yearsVolcanoThe activity is active, Mt. AsamayamaMt. EboshidakeTogether with three volcanic bodies such asAsama mountain rangeOrAsama Eboshi Volcanic GroupCollectively called.So fareruptionMountain collapseRepeatedly, it became the present appearance.The traces of large-scale collapse of the mountain body and the outflow of collapsed soil are far away in Gunma Prefecture.Maebashi OfplateauThick on top etc.SedimentRemains as.It is Maekake volcano that is currently erupting.From the mountaintop craterSmokeThere is a complex caldera around it, and Maekakeyama is on the west side of the inner outer ring mountain.The caldera on the north side has collapsed due to the lava flow that flowed from the top of the mountain to "Onioshidashi Rock".On the outer caldera,Mt. Kurofuyama,Asan, Kengamine, etc.Japanese Meteorological AgencyIs designated as an active volcano of rank A as "an active volcano with a particularly high activity of 100 years or 1 years".[2].

1949 years(Showa24) On September 9th, the mountain areaJoshinetsu Kogen National ParkSpecified in[3].. 2007,Top XNUMX geological features in JapanWas selected.Nihon Hyaku Meizan(Japan's hundred famous mountains)[4]as well as the Hana no Hyakumeizan(One hundred mountains of flowers)[Annotation 2]Has been selected.

Volcanic activity

Activity history of Mt. Asamayama

It is classified into three types according to the location of the crater and the nature of the lava.[6].

Black spot stage (about 13-2.6 years ago)
basaltAndesite and andesitic lava.The current Mt. Kurofuyama is a horseshoe-shaped caldera that opens to the east.This horseshoe-shaped caldera is about 2.4 to 2.3 years ago in Tsukahara, Shiozawa, and Okuwa.Debris avalancheIs believed to have been formed by the outbreak of.The volume of the collapsed mountain body is 4 km3Is estimated to be[7], Centered near the current Yunohira before the formation of the calderaFire conduitWith about 2,800-2,900mMount FujiIt is believed to have been a type of stratovolcano.Traces of mudflow generated at this time are around Maebashi Plateau and Mt. AsamayamaFlow mountainCan be confirmed as.Also,Minami KaruizawaThen in this mud flowYukawaWas dammed up and a large lake was formed (Minami Karuizawa Lake stratification).Fang lava group, Kengamine lava group, Mitsuone lava group, etc. as lava flow,Volcanic ashAsNorthern Kanto loam layerItahana brownpumiceForming a group (BP / F)[8]..There is no activity between about 8 to 7 years ago and about 4 to 3 years ago, and it is in a dormant period.
Buddha rock period (about 2.6 to about 1.3 years ago)
Looking at Mt. Asamayama from the south, you can see the bulge on the right side of the mountain body.This is Buddha Rock Volcano. The activity started after the collapse of the Mt. Kurofuyama mountain body, and the altitude of the mountain body at its peak exceeded 2,000 m above sea level.Rich in viscosityEnstatite-AmphiboleDay sightQuality and rhyolite[9]Thick lava flow repeatedly flowed out, forming a gently sloping volcanic body.Adjacent to KaruizawaHanareyamaWas formed by an eruption about 2.6 years ago, the earliest of the Buddha rock period.Lava domeIs. Also,Shiraito FallsFrom the pumice layer of the Buddhist rock period deposited on the lake strataspringare doing.Gunma PrefectureMaebashi OfIwagami Inari ShrineIt is in"Iwagami's flying stoneIs estimated to have been reached by the mudflow that occurred in the collapse about 2 years ago.[10].
About 1.6 years ago, the Itahana Yellow Pumice Formation (YP) of the Northern Kanto Loam Formation andKomorothe firstPyroclastic flow, Colorful volcanic ash, AsamaKusatsuTephraThe largest eruption among Asama volcanoes (total eruption volume 4.38 DRE km)3)There has occurred[8].Manza KazawaguchiSeen aroundbeigeThe colored cliff is the ejecta at this time.It is believed that this eruption formed a caldera.In addition, the total amount of ejecta from the eruption at this time was 10.95km.3Volcanic Explosivity Index: VEI is 6, this isMount PinatuboTotal amount of ejecta from the 1991 eruption (10km)3), It was a large scale.
Pre-season (about 1.3 years ago-present)
It is an andesitic compound volcano, and after the activity of Buddhist volcano, eruption started at Asama Maekake volcano (Asama volcano in a narrow sense), which is the middle point between Mt. Kurofuyama and Buddhist volcano. Thirteen pumice fall layers have been identified, with intervals between large-scale eruptions believed to be 13-700 years.[11]..Large eruptions of the 4th century, 1108, and 1783 are known, accompanied by lava and pyroclastic flows. Eruption of 1108 (total amount of ejecta 1.55 DRE = 3.875km)3) Is 1783 (total amount of ejecta 0.73km)3A small caldera-like topography was formed on the mountaintop on a scale about five times that of the eruption of).Currently, the activity is relatively calm, but there is no sign that the activity has declined.[12].
In historical books, etc., it erupted in the following years (TaiziHas a damage record).
  • 685,1108, 1281 ?, 1427 ?, 1527-1528,1532, 1582 ?,1596, 1598, 1604, 1605, 1609, 1644-1645,1647-1649 year、1651-1652年、1653または1655-1659年、1669年、1704年、1706年、1708-1711年、1717-1718年、1720-1723 year, 1728-1729, 1732-1733,1754, 1776-1777,1783 years(Tenmei eruption・ Onioshidashi),1803, 1815, 1869, 1875, 1879, 1889[13], 1894, 1899, 1900, 1901, 1902, 1904, 1907, 1908 ?,1909, 1910,1911-1914 year, 1916, 1917, 1919,1920, 1921, 1922, 1927,1928, 1929,1930,1931, 1932, 1934,1935,1936, 1937, 1938, 1939, 1940, 1941, 1942, 1944, 1945, 1946,1947, 1951, 1952, 1953, 1954, 1955,1958, 1959,1961、1965年、1972年、1973年、1982年、1983年、1990年、2004年、2008年、2009年、2015年、2019年

Major unrecorded eruptions

  • 685(Emperor TenmuAugust 14:Asuka Period) 『Japanese calligraphy]Hakuho Earthquake5 months laterShinano countryThere is a description that ash fell and vegetation died in (currently Nagano Prefecture). It was supposed to be an eruption of Mt. Asamayama[14], It is not specifically described as Mt. Asamayama, but rather from the wind direction to the west, for exampleMt. Niigatayakeyama,Mt. YakedakeIt is said that there is a possibility of eruption such as[15].
  • 1108 years(Kajo3 years,TenrenFirst year:Heian period) Tenjin large-scale eruption.The eruption site is Mt. Maekake, a large eruption with an estimated 30 billion tons of ejecta.Volcanic Explosivity Index: VEI5.Ueno country(Currently Gunma Prefecture) Volcanic products piled up all over the area, causing a devastating blow to the fields. "Middle right』Recorded in.According to the article on September 9, 5st year of Tennin, 40 years before this yearCalendarThe eruption increased during the year (1065-1069), and after that, the eruption increased slightly, and on July 7, the same year, a large eruption suddenly occurred.It is written that the eruption smoke soared high in the sky, the ejecta spread all over the country of Ueno, and all the fields were buried.[16]..The fields developed for reconstructionAustralianIs privatized and furtherManorHas evolved into.This eruption was an opportunity to promote the conversion of Ueno to a manor.Also on the Nagano sidePyroclastic flow(Oiwake pyroclastic flow) runs down about 15 km,YukawaIt is possible that several villages at the foot of the mountain were buried.It is said to have been a larger eruption than the Great Tenmei Eruption.Recently, the temperature in the northern hemisphere at the beginning of the 12th century decreased by about 1°C, and the darkLunar eclipse, it was suggested that the eruption of Mt.[17] .
  • 1128 Daiji3 years large scalemagmaThe eruption and eruption location is Mt. Maekake.Volcanic Explosivity Index: VEI4.
  • 1532 Enjoyment4 years The eruption site is near the summit.The volcanic bombcraterA mudslide occurred on the Nagano Prefecture side, washing away several villages and damaging highways.Near the middle stream, there remains a 'Nanahiroishi' stone with a diameter of 8m or more.Volcanic Eruption Index: VEI25.
  • 1582 Tensho10 『Tomonin Diary"" ""Japanese history, Etc., Mt. Asamayama erupted on February 2th,京都It is said that it was possible to observe even from[18]..This eruption is justOda NobunagaThe army ofTakeda RyoInvasion ofKoshu conquest) Was started shortly after, so in Takeda territoryNational peopleAnd the lordKatsuyori TakedaZhucheng in the Takeda territory fell without resistance to the Oda army on the day of this eruption.[19].
  • 1721 Kyoho6 years pyroclastic material descent.Fifteen climbers were killed and one seriously injured due to a volcanic bomb.Volcanic Explosivity Index: VEI15.
  • February 1783, 8 (Tenmei37/8Tenmei eruption Total amount of ejecta 4.5 × 108m3, Volcanic Explosivity Index: VEI4.
    • Mt. Asamayama, who resumed activities on April 4 (the lunar calendar, the same applies to this item below), continues to work on May 9 and June 5, repeating eruptions and lulls every month. It was.
    • From June 6th, eruptions and explosions began to repeat every day.As the days went by, the intervals became shorter and the intensity increased.Edo,KansaiBut the doorShojiVibrated.
    • The eruption that lasted for three days from July 7 caused a catastrophe.First, Azuma in the northeast and northwest directions (V-shaped from Mt. Asamayama to the north)Pyroclastic flow(All of these pyroclastic flows flowed down to the Gunma prefecture side).Subsequently, a large amount of ejecta accumulated on the hillside due to the activity that lasted for about 3 months collapsed without being able to withstand the tremors of the explosion and eruption.These became large-scale landslides and rushed to the north at high speed.Regarding the explosion sound around July 7th京都,Shikoku,HiroshimaI'm suspiciousNagasakiThere is also a record that it was heard.A huge, high-speed stream flows down while scooping out the ground at the foot of the mountain.Kamahara Village(CurrentTsumagoi VillageLarge print鎌原Area) andNaganohara TownDestroyed part ofAzumagawaFlow intoNatural damFormed and caused a river channel blockage.The natural dam broke down immediatelyLaharIt causes a great flood next to it and becomes the mainstream while swallowing the villages along the Agatsuma River.Tone RiverFrom the current Maebashi cityTamamura TownThe damage has reached the point.The flooded Tone River carried everything that was washed away downstream, and was the main stream of the Tone River at that time.EdogawaMud flow also flowed in, and many bodies were found in the lower reaches of the Tone River.EdogawaWas launched into.At that time, the number of victims was 1624 (including more than 1,400 in the Kozuke area alone), 1151 lost houses, 51 burned houses, and 130 collapsed houses.[20]..Finally, "Onioshidashi lava" flowed down to the north, and it is said that the Mt. Asamayama eruption in Tenmei 3 was heading toward convergence.
    • Lava flows and pyroclastic flows have long been thought to be the cause of sediment movement, but low-temperature dry powder flows were the main cause of disasters.[21]..A geological survey of Kamahara Village, which suffered the most damage, revealed that only about 3% of the ejecta in the 5rd year of Tenmei were ejected.Also in 1979 (ShowaFrom 54 years)Tsumagoi VillageIn the excavation survey conducted by the company, three private houses could be confirmed, but it is known that the main component is earth and stone at room temperature because very few excavated items were burnt or burned.In addition, it is thought that part of the pyroclastic lava is part of the pyroclastic lava that was deposited near the crater, fused, reflowed, and flowed down. Volcanic ash is far away in excavations in the 3sTochigi OfKinugawaからIbarakiKasumigaura,SaitamaIt was confirmed that it was descending to the north[22]..In addition, a large amount of accumulated volcanic ash caused a large amount of sediment to flow into the main river of the Tone River, causing secondary disaster damage such as flood damage in Tenmei 3 and flood damage in Tenmei 6.[23][23].
    • The eruption at this timeGreat Famine of TenmeiCausesTohoku regionIt has long been recognized that it killed about 10 people, but it cannot be said that it is a direct cause because the poor harvest due to the unseasonable climate in the Tohoku region has already occurred since the 1770s.On the other hand, in the same year, it is in the northern part of the Tohoku region.Mt. IwakisanNot only erupted (April 4, March 13, Tenmei 3),アイス ランド OfLaki volcano(Lakagígar) giant eruption (Lakigígar rift eruption, June 6)GrimsvotonA long-term eruption of a volcano (Grímsvötn) has occurred, resulting in an enormous amount of orders of magnitude.Volcanic gas ThestratosphereRise to.The dust from the eruption covers the northern half of the earth,Amount of solar radiation reaching the groundBecause it reducedNorthern hemisphereToCold injuryBrought about.For this reason, the famine that had already become serious was spurred and the situation was exacerbated. "Volcanic winter # Recorded history caseSee also.
  • March 1937, 12 (Showa 3) Small eruption.Heavy tephra fall in Karuizawa and around the foot of the mountain[24].
  • June 1938, 13 (Showa 6) A large amount of ash fall.Total amount of ejecta 7 × 25m3, September 9, 26:13 Eruption height 43m.Volcanic Explosivity Index: VEI 8,200.
  • August 1947, 22 (Showa 8) Eruption height 14 m, 12,000 victims due to volcanic bombs.Volcanic Explosivity Index: VEI11.
  • A large explosion occurred at 1950:25 am on September 9, 23.A high school student climbing a mountain died after receiving a volcanic bomb in his head.Ibaraki prefecture, Saitama prefecture, ash fallTokyoIt was also seen in.Explosion soundAichiNagoya cityArrived until.[25]A huge rock mass called Sentoniwa that erupted from this eruption exists near the summit crater on the Gunma prefecture side.
  • 1958年(昭和33年)11月10日 午後10時50分、突然大爆発して噴煙が高さ 7,000 - 8,000mに達した。噴出物総量3.6×105m3, Volcanic Explosivity Index: VEI1.
  • 1973年(昭和48年)2月1日 午後7時20分に爆発、小規模な火砕流発生、火炎の高さは500mに達する。約1ヶ月前から活発な火山性地震を観測(1月13日、14日合計150回超)し、5月24日まで微噴火まで合わせ87回の噴火と活発な活動が続いた[26]..Volcanic Explosivity Index: VEI2.
  • April 1983, 58 (Showa 4) Explosion,Fukushima OfThe Pacific OceanObserved ash fall on the shore.Volcanic Explosivity Index: VEI 0.9.
  • 2004 years(Heisei16年)9月1日 20時20分頃 中規模の爆発的噴火を確認。噴煙高度3500-5500m。小康状態の後、9月14日 - 18日にかけて、及び9月23日には中規模の噴火[27].. No eruption observed after November 11th[28]..Volcanic Explosivity Index: VEI1.
  • August 2008, 20 Confirmed a small-scale eruption[29].
  • February 2009, 21 Eruption confirmed.Kanto Plain10g / m over a wide range of2 -50g/m2Ash fall.There is a related article on Wikinews.[30]Volcanic Explosivity Index: VEI1.
  • 2015
    • 0June 6th, around 16:9 am,Empty shakeSmall-scale eruption that does not observe.Confirmed a small amount of ash fall from north to northeast[31].
    • 0A very small eruption occurred around 6:19 on June 17th.[32].
  • 2019 years(ReiwaFirst year)
    • 080A small eruption occurred at around 7:22 on the 08th.On the same day, Mt. Asamayama announced a crater area warning (eruption alert level 3 (mountain entry restrictions)).[33].
    • 0Eruption at around 8:25 on August 19

Disaster prevention

August 1911, 8,Earthquake Investigation CommitteeIs the first in Japan in collaboration with Nagano Weather StationVolcano observatoryWas installed on the west side of Mt. Asamayama.[34].

Evacuation routes etc. are summarized from past eruption casesHazard mapIs being created[35]..Also, in Komoro City, Nagano PrefectureChikuma RiverTraces of lava flow flowing to the riverside and Gunma prefecture sideAzumagawaThen, due to the collapse of the mountain body, a large scaleEarth and stone flowThere is evidence that sediment has accumulated in a wide area up to the vicinity of Maebashi City, and it is not just a problem near the mountain body.

Volcanic eruption prediction liaison meetingIt has been selected by the volcano as a volcano that requires the improvement of monitoring and observation system for volcanic disaster prevention.[36]. Also,Earthquake Research Institute, University of TokyoObservations are carried out 365 hours a day, 24 days a year.


Topography of Asama volcano

  • Mt. Maekake-There is a central crater hill and a Busan crater (current crater).
  • Mt. Kurofuyama --The caldera edge of the ancient stratovolcano.
  • Later volcano
    • Small Mt. Asamayama- Lava dome..3.8km east of Busan crater.
    • Hanareyama --Lava dome, relative height is about 200m, 10km southeast of Busan crater.
    • Mt. Ishizune-A lava dome located on the south side of Mt. Maekake, with a relative height of about 250m and 3.3km southwest of the Busan crater.


At the southern foot of Mt. Asamayama, on the Nagano sideKaruizawaHowever, on the Gunma prefecture side at the northern foot of the mountain, Tsumagoi Village and Naganohara Town, Agatsuma DistrictKita KaruizawaAnd scenicSummer resortDevelopment has been progressing for a long time.The northern foothills area has a characteristic topography formed by volcanic activity, which will be described later, and in 2016.Japan GeoparkCertified by[37].

  • Onioshidashi, Onioshidashi leaked in the pastLava flowTraces ofDemon Extrusion Gardenas well as the Onioshidashi SengenIt is maintained as.In Asama GardenAsama Volcano MuseumThere is.
  • Shiraito Falls,Volcanic ejectaFrom the horizontal plane wherespringBlows outwaterfallIs a famous place.
  • Mt. Asamayama lava tree type, During the great eruption of Mt. Asamayama in the 3rd year of Tenmei, a pyroclastic flow was generated and flowed to the Gunma prefecture side.Native forestReached.The hot pyroclastic flow wraps around the trees, burning down the growing trees.Eventually, the burnt residue of the tree decayed, leaving only a well-like hole (although it is called a "lava tree type", it is known that it was actually formed by a pyroclastic flow).Hundreds of tree types have been found in Tsumagoi Village, of which about XNUMX are in Tsumagoi Village.Board of educationConservation activities to regularly remove soil and dead leaves accumulated in the tree mold and maintenance of the surrounding area are being continued.Trees range in size from small ones with a diameter of several tens of centimeters and a depth of one meter to huge ones with a diameter of more than two meters and a depth of five meters or more.In the treeHikarigokeSome of them are clustered, and in the maintained area, they can be easily observed together with the tree type.From the country on August 15, 1940Special Natural MonumentSpecified in.

Source river

The source of the followingRiverRespectivelySea of ​​JapanThe Pacific OceanFlow to[38].

Flora and fauna

Mt. AsamayamaSilabiso,Abies mariesiiNature of the subalpine zone centered onVegetationLeaving aroundLarch OfNatural forestIs widespread and is home to many wild animals.Among them,Golden eagle,Asiatic black bearAsama designated by the country because it is important as a habitat forWildlife reserveDesignated as (Large-scale habitat) (Area 32,218)haOf which, the Special Protection Area 947ha).

Faith and folklore

"Asama" is an ancient word for volcanoes.Mount FujiEnshrine the god ofShrine Asama ShrineFor the same reason, it is called (Sengenjinja).Mount Aso"Aso" is also said to be a similar word. Mt. Asamayama, like many mountains, has been around for a long timeMountain worshipAsama Shrine (the deity is different from the usual Asama Shrine) is enshrined.

Snow shape
On the south and north slopes of Mt. AsamayamaSpring:To become andSnow shapeAppears.On the south slopecarpThe pattern of is an upside-down horse on the north slope ((I.e.Seems to have his head down) By the time he leavesSeedbedThere is a custom to prepare for[39].


The area near the crater of Mt. Asamayama has been off limits since 1972 due to the eruption of the volcano.Although the regulation was lifted during the subsequent calm period, depending on the volcanic activity, mountain climbing restrictions may be imposed as an exclusion zone within a certain straight line distance from the crater by the local government.

As of 2022, climbing from the Komoro City side of Nagano Prefecture to Mt. Maekake is permitted.The Mt. Asamayama Geopark Promotion Council, which will be built in Naganohara Town and Tsumagoi Village on the Gunma Prefecture side, plans to develop a mountain trail aiming for opening in 2025 in consultation with the Ministry of the Environment, and will also set up a shelter in preparation for an eruption.[37].

  • Celebrity climbing record
  • The eruption forecast has been "Volcanic Alert Level 2018" (note that it is an active volcano) since August 8, 30.[41].
  • Karuizawaguchi:National Highway 146"Mine no Chaya" course.
    • No trespassing around the Mt. Asamayama crater (regulated within 0.5 kilometers from the crater).
      • Small Mt. Asamayama ・ It is possible to climb the mountain trail leading to Mt. Ishizune.
  • Komoroguchi: "Black Spot Course / Volcano Museum Course"
    • No trespassing around the Mt. Asamayama crater (regulated within 0.5 kilometers from the crater).
      • You can enter Mt. Maekake.

 There used to be a mountain trail from Tsumagoi Village via Mt. Kurofuyama, but the mountain trail collapsed due to rain and is now out of service.

The work that became the stage

  • As the sun goes down, I can't even see Asama. Shimazaki Fujimura(Chikuma River Travel Information Song)
俳 句
  • Tsumagoi-Tenmei XNUMXrd year Mt. Asamayama eruption secret story / Junya Fukumoto
  • Mt. Asamayama swallows history-The Great Eruption of Tenmei / Author: Seiichi Konishi, Picture: Sumio Koizumi
  • Mt. Asamayama eruption / Takashi Watanabe
  • Mythical climate Fuji Asama mountain turmoil / Masanori Yoshii
  • People who protected Karuizawa-Mt. Asamayama Memories of the US Army Exercise Area Opposition Movement / Kenji Tabei
  • In the village where Mt. Asamayama can be seen / Fumiko Minami, Katsuko Ikeda
  • Asama / Kazuhei Tatematsu
  • Konohana Kitan Vol. 10 Ieji / Sakuya Amano (manga work)
  • Getter RoboSeries / Ken Ishikawa,Nagai Hao(Manga, Anime) Getter Robo Operation base research institute exists in Mt. Asamayama.

Related images


[How to use footnotes]

注 釈

  1. ^ a b The highest point is the elevation point at the eastern end of the summit crater, and the third grade at the southern end of the summit.Triangular point(Point name "Mt. Asamayama" 2,493.936m) is[1].
  2. ^ Representing Mt. Asamayama in this bookAlpine plant OfMurasakiIntroduced[5].


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  17. ^ Caused by Mt. Asamayama, the European famine 900 years ago?Traces on glaciers, (2020-05-20), https://www.asahi.com/articles/ASN5L6QJQN5HULBJ012.html 
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