Hallasan () is a

shield volcano A shield volcano is a type of volcano named for its low profile, resembling a shield lying on the ground. It is formed by the eruption of highly fluid (low viscosity) lava, which travels farther and forms thinner flows than the more viscous lava ...

comprising much of

Jeju Island Jeju Island (Jeju language, Jeju/) is South Korea's largest island, covering an area of , which is 1.83% of the total area of the country. Alongside outlying islands, it is part of Jeju Province and makes up the majority of the province. The i ...

in South Korea. Its summit, at , is the highest point in the country. The area around the mountain is a designated

national park A national park is a nature park designated for conservation (ethic), conservation purposes because of unparalleled national natural, historic, or cultural significance. It is an area of natural, semi-natural, or developed land that is protecte ...

, named

Hallasan National Park Hallasan National Park () is located on and around the mountain Hallasan in Jeju Province, South Korea. It was designated as the 9th national park in 1970. Hallasan is a shield volcano that is the highest mountain in South Korea. It was designa ...

. Hallasan is commonly considered to be one of the three main mountains of South Korea, along with

Jirisan Jirisan () is a mountain located in the southern region of South Korea. It is the second-tallest mountain in South Korea after Jeju Island's Hallasan, and is the tallest mountain in mainland South Korea. The 1915m-high mountain is located in ...

and

Seoraksan Seoraksan (), or Mount Sorak, is the highest mountain in the Taebaek mountain range in the Gangwon Province in eastern South Korea. It is located in the Seoraksan National Park, near Sokcho. After the Hallasan volcano on Jeju Island and ...

. The Hallasan Natural Reserve was designated as a South Korean

Natural Monument A natural monument is a natural or cultural feature of outstanding or unique value because of its inherent rarity, representative of aesthetic qualities, or cultural significance. They can be natural geological and geographical features such as w ...

number 182 on October 12, 1966.

Names

Alternate English names for the mountain include ''Hanla Mountain'' and ''Mount Halla'', and older English sources refer to the peak as ''Mount Auckland''. Hallasan is written in Hangul as if it were ''Hanrasan'' (), but is still pronounced ''Hallasan''. In the past, Hallasan has been known by numerous other names in Korean including ''Buak'' (), ''Wonsan'' (), ''Jinsan'' (), ''Seonsan'' (), ''Dumuak'' (), ''Burasan'' (), ''Yeongjusan'' (), and ''Hyeolmangbong'' (). Jeju Island

Geology and geography

Hallasan

Hallasan is a massive

which forms the bulk of

and is often taken as representing the island itself. There is a Korean traditional local saying that "Jeju Island is Hallasan, and Hallasan is Jeju." The mountain can indeed be seen from all places on the island, but its peak is often covered in clouds. The soil of Hallasan is mostly made out of

volcanic ash Volcanic ash consists of fragments of rock, mineral crystals, and volcanic glass, produced during volcanic eruptions and measuring less than 2 mm (0.079 inches) in diameter. The term volcanic ash is also often loosely used to r ...

, volcanic sand, and

lapilli Lapilli (: lapillus) is a size classification of tephra, which is material that falls out of the air during a volcanic eruption or during some meteorite impacts. ''Lapilli'' is Latin for "little stones". By definition lapilli range from in dia ...

. The organic contents of the soil are higher than any other soil in South Korea, and

drainage Drainage is the natural or artificial removal of a surface's water and sub-surface water from an area with excess water. The internal drainage of most agricultural soils can prevent severe waterlogging (anaerobic conditions that harm root gro ...

is also better than any other place in South Korea, but its soil is relatively infertile. The volcanic island was constructed, starting in the

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58continental shelf A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an islan ...

, which is about 100 m (300 ft) below sea level in the area. Eruptions of

basalt Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial ...

and

trachyte Trachyte () is an extrusive igneous rock composed mostly of alkali feldspar. It is usually light-colored and aphanite, aphanitic (fine-grained), with minor amounts of mafic minerals, and is formed by the rapid cooling of lava (or shallow intrus ...

lava Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a Natural satellite, moon onto its surface. Lava may be erupted at a volcano or through a Fissure vent, fractu ...

built the island above sea level, and it now reaches a height of . A large

volcanic crater A volcanic crater is an approximately circular depression in the ground caused by volcanic activity. It is typically a bowl-shaped feature containing one or more vents. During volcanic eruptions, molten magma and volcanic gases rise from an ...

over in diameter tops the volcano. About 360

parasitic cone A parasitic cone (also adventive cone, satellite cone, satellitic cone or lateral cone) is the cone-shaped accumulation of volcanic material not part of the central vent of a volcano. It forms from eruptions from fractures on the flank of the ...

s, or ''oreum'' () in the

Jeju language Jeju (Jeju: ; Jeju RR: , or , or ), often called Jejueo or Jejuan in English-language scholarship, is a Koreanic language originally from Jeju Island, South Korea. It is not mutually intelligible with mainland Korean dialects. While it was hi ...

, are found on the volcano's flanks. Most of them are

cinder cone A cinder cone or scoria cone is a steep, volcanic cone, conical landform of loose pyroclastic rock, pyroclastic fragments, such as volcanic ash, clinkers, or scoria that has been built around a volcanic vent. The pyroclastic fragments are forme ...

s and

scoria cones A cinder cone or scoria cone is a steep, conical landform of loose pyroclastic fragments, such as volcanic ash, clinkers, or scoria that has been built around a volcanic vent. The pyroclastic fragments are formed by explosive eruptions or lav ...

, but there are also some

lava dome In volcanology, a lava dome is a circular, mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano. Dome-building eruptions are common, particularly in convergent plate boundary settings. Around 6% of eruptions ...

s and about 20

tuff ring Phreatomagmatic eruptions are volcanic eruptions resulting from interaction between magma and water. They differ from exclusively magmatic eruptions and phreatic eruptions. Unlike phreatic eruptions, the products of phreatomagmatic eruptions cont ...

s near the coast and offshore, which were formed by underwater

phreatic eruption A phreatic eruption, also called a phreatic explosion, ultravulcanian eruption or steam-blast eruption, occurs when magma heats ground water or surface water. The extreme temperature of the magma (anywhere from ) causes near-instantaneous evap ...

s. According to

Goryeosa ''Goryeosa'' (), or ''History of Goryeo'', is an extensive historical record of the Goryeo dynasty, compiled by the officials of Goryeo's successor state, Joseon. Its compilation started during the reign of Taejo of Joseon, Taejo (the founding ...

, its last eruption was in 1007 CE, while geological evidence suggests its last eruption was around at least 2,000 years ago. This puts the volcano into the active classification, meaning it has erupted in the last 10,000 years. The designation as active is not agreed to by all, as more monitoring and study are needed to better understand the volcano.

Baengnokdam

There is a

crater lake Crater Lake ( Klamath: ) is a volcanic crater lake in south-central Oregon in the Western United States. It is the main feature of Crater Lake National Park and is a tourist attraction for its deep blue color and water clarity. T ...

on Hallasan called Baengnokdam (), meaning "white deer lake". It is formed by the collapse of the top of the ridge by the movement of magma underground. There is a legend attributing the name of the lake to otherworldly men who descend from heaven to play with white deer. Depending on the season, the circumference of the lake is up to with a depth up to about . The configurative rocks of the eastern and western walls of Baengnokdam are different. The eastern wall is covered with basalt lava thick at its top. In the lower part, there is a high-concentration stream sediment layer of the Tamna layer. The western wall is made of the trachyte lava dome. The volcanic wall formed by the eruption of the lava should be composed of lava, analysis. However, the eastern wall is composed of the clastic sedimentary sediments, so it is not a crater by lava eruption but a pit crater. Namely, the trachyte magma, which formed the Baengnokdam trachyte, was elevated on the dome, and the trachyte magma formed lava dome at its top. The inclination and direction of the Tamna Formation of Baengnokdam cannot be measured directly at Baengnokdam, but it is N10W of slope and 30NE of slope measured near the valley below North Baengnokdam, above sea level.

Impact of topography

Tendency of wind change by Hallasan

In order to understand the tendency of temperature change in Jeju Island, the short-term forecasting model of Halla, the weather data of the Korean peninsula, and the wind vectors from the AWS are analyzed. When the south winds flow into the sea, sea winds form around Hallasan, and a sea breeze is formed on the downwind side of the sea. On the coast, winds and the sea breezes gather around the coasts to form a persistent

eddy Eddy may refer to: * Eddy (surname), surname used by descendants of a number of English, Irish and Scottish families * Eddy (given name), male given name * Eddy (fluid dynamics), the swirling of a fluid and the reverse current created when the fl ...

, and the highest temperature occurs in the region where the eddy occurs.오영숙, 김동호, 송기옥(2006.4),
한라산 지형 효과가 제주도의 국지 기온에 미치는 역할 (The role of Hallasan topography on local temperature in Jeju Island)".
한국기상학회 학술대회 논문집

Tendency of maximum temperature by Hallasan

In order to understand the tendency of maximum temperature in Jeju Island, the area where the highest temperature occurred when the wind was weak was surveyed and analyzed. In the morning, when the reverse layer is formed and the wind is weak, the warm air of the lower layer is raised when the air movement between the upper and lower layers is blocked, and it is placed on the upper floor by the sea breeze, which affects the temperature rise in the mid-mountainous area. The occurrence of the highest temperature coincides with the formation position of the eddy, and when the wind is weak, the eddy forms in the middle mountain region. When the wind is weak, the warmth is accumulated in the middle layer, so the maximum temperature in the mid-mountainous area is higher than the maximum temperature of the low-altitude coastal area by about , and or higher on the downwind side. When the wind is blowing at , a weak sea breeze coming from the sea is formed on the coastal area and peak temperatures are mainly observed during the daytime.

Tendency of minimum temperature by Hallasan

The change of the minimum temperature varies depending on the degree of cooling of Hallasan and the intensity of the wind speed. When the wind blows due to the predominant sea breeze, the air cooled in Hallasan descends to the coastal area and induces a decrease in temperature. When the synoptic wind blows strongly, the cold air of Hallasan moves to the downwind side and the lowest temperature appears. The lowest temperature in the downwind area is lower than in other areas, and the lowest temperature often occurs at night. When the weak northwestern synoptic winds blow, low temperatures occur in the eastern part of Jeju Island. The chill of the top of Hallasan descends downhill along the mountain range and is collected in the eastern part of Jeju Island so the morning temperature drops considerably.

Inter-regional temperature variation by Hallasan

For the last five years, the deviation of temperature (maximum temperature - minimum temperature) increased in spring between March and May. The reason for the large deviation in spring is because the phenomenon occurs frequently by Hallasan.

Ecosystem

Hallasan was isolated from the mainland for a long time and its species were able to become unique and different from mainland species. The elevation of the mountain causes various plant species to live there. The mountain became a habitat for plants that live in low elevation and plants that live in high elevation. 50 or more unique species live in Jeju Island, especially in high elevation area in Hallasan. Various animal species also live on the mountain. Because of the geography of the mountain, the same species evolved in different ways after thousands of years. Just like plant species, animal species originally living in cold and hot climates use the mountain as their habitat. There are a total of 160 bird species that use Hallasan as a habitat. Only 19 species are considered as a natural monument and protected by the government. Ravens are commonly seen in the hiking trail. A total of 3,315 insect species live on the mountain. 254 spider species also live there. A study found that spider habitat is concentrated more on the north side of the mountain. Ticks live on the mountain and caused much damage to Jeju residents long ago. The damage caused by ticks continues. Six tick species cause problems for domestic animals.

Flora

According to the world floral region, Hallasan belongs to the temperate subregion with Yangtze River basin and southwest Japan. From the coast to the top of the Hallasan, plants are distributed vertically from the subtropical plants to the alpine plants due to the environmental gradient. Of the 4,000 species of vascular plants native to Korea, about 400 species are estimated to be endangered or potentially rare. Especially, 23 species-specific wild plants designated by the Ministry of Environment (a total of 59 species) are distributed in Jeju Island and 6 of them can be found in the natural reserve area of Hallasan. Also, about 50 kinds of special plants are distributed in Jeju Island, especially in the highlands of Hallasan.

Fauna

Because of the geographical character of the island, there are many subspecies due to isolation even though they are the same species. Also, Hallasan is a place where the polar animal and the tropical animal coexist due to the difference of the climate zone according to the elevation.

Mammals

The mammals of Jeju Island are distributed among five orders and 114 families and five species. Thus, the distribution of mammals in Jeju Island is very poor in species and numbers because Jeju island became isolated from the Korean peninsula long ago. Their population has declined due to the decrease in food because of the use of rodenticides and pesticides in recent years and indiscreet fishing. Weasels, badgers, and gazelles inhabit Hallasan. The number of weasels and badgers is declining. Tiger, boar and Formosan deer are already extinct. Roe deer, the largest mammal in Hallasan, was once in danger of extinction, but now its population has increased due to protection policies and much effort by the islanders.

Amphibians and reptiles

Most amphibians and reptiles on Jeju Island are indigenous animals but there are some invasive species from Japan and China. Mt. Halla is particularly well-suited for amphibians and reptiles as a hideout, with well-developed grasslands and marshlands, and is rich in food.

Birds

There are 364 kinds of birds in Jeju Island, 91 kinds of passing birds, 100 kinds of birds in winter, 42 kinds of resident birds and 43 kinds of vagrants. Among the birds in Jeju Island, except for the species that live in habitat for migratory birds and coastal regions, there are 160 species mainly inhabiting Mt. Halla. There are 19 species designated as natural monuments.

Temple

The mountain is home to Gwaneumsa (), the oldest

Buddhist temple A Buddhist temple or Buddhist monastery is the place of worship for Buddhism, Buddhists, the followers of Buddhism. They include the structures called vihara, chaitya, stupa, wat, khurul and pagoda in different regions and languages. Temples in B ...

on the island. The temple was originally built during the

Goryeo Goryeo (; ) was a Korean state founded in 918, during a time of national division called the Later Three Kingdoms period, that unified and ruled the Korea, Korean Peninsula until the establishment of Joseon in 1392. Goryeo achieved what has b ...

period (1046–1083) during the reign of King Munjong. Like many other temples in Korea, Gwaneumsa was destroyed in 1702 and closed for 200 years. The temple was rebuilt in 1908. It propagates

Buddhism Buddhism, also known as Buddhadharma and Dharmavinaya, is an Indian religion and List of philosophies, philosophical tradition based on Pre-sectarian Buddhism, teachings attributed to the Buddha, a wandering teacher who lived in the 6th or ...

again in Jeju Island. There is a memorial site outside the temple to commemorate the victims of the

Jeju uprising The Jeju uprising (in South Korea, the ''Jeju April 3 incident'', ) was an insurrection on Jeju Island, South Korea from April 1948 to May 1949. A year prior to its start, residents of Jeju had begun protesting elections scheduled by the Un ...

that took place between 1948 and 1950. It is one of the most visited places on the island. The mountain is also the location of Jonjaamji, a pagoda preserving relics of the Buddha.

Trails

There are five hiking trails on Hallasan. * Gwaneumsa Trail (관음사 탐방로/) - 8.7 km * Eorimok Trail (어리목 탐방로/어리목 ) - 4.7 km * Seongpanak Trail (성판악 탐방로/) - 9.6 km * Yeongsil Trail (영실 탐방로/) - 3.7 km * Donnaeko Trail (돈내코 탐방로/돈내코) - 9.1 km The Donnaeko trail was reopened to the public on December 4, 2009, after a fifteen-year hiatus. Only the Gwaneumsa and Seongpanak trails lead to the summit. The Donnaeko, Eorimok and Yeongsil courses only go as far as Witse Oreum (), as the rest of the trail leading to the peak has been closed off since 1994 in order to restore and protect the vegetation.

Transport

Gwaneumsa Trail

To go to Gwaneumsa Trail by car, you should use road number 1117 which connects Jeju Arra-dong Mountain and Tamra Education Center and Cheon-Wangsa. From Jeju city hall to Gwaneumsa Information Center, it takes about 25 minutes and from Seogwipo city hall, it takes about 50 minutes. If you want to use public transportation, ride Jeju city bus number 475. This bus does not enter the city, so riders have to get off and transfer at the entrance of Jeju University. In the past, it operated only on weekends and holidays, but it can be used on weekdays since the 2017 bus route reorganization. If you have to take a bus to Jeju city or Seogwipo city, the closest stop is Jeju medical center at 5.16 road. It takes about 40~50 minutes on foot. This bus comes until 20:20.

Eorimok Trail

To go to Eorimok Trail by car, you should use road number 1139 (or 1100), which connect Jeju City and Seogwipo City Jungmun-dong. From Jeju city hall, it takes about 35 minutes and from Jungmun-dong, it takes about 50 minutes. If you want to use public transportation, ride bus number 240. (Dispense interval about 1hr.)

Seongpanak Trail

To go to Seongpanak Trail by car, you should use road number 1131 (or 516) which connect Jeju city and Seogwipo city. From Jeju city hall to the Seongpanak Information Center, it takes about 30 minutes. From Seogwipo city hall, it takes about 40 minutes. If you want to use public transportation, ride buses on road 516, which are 181, 182, 281. Since these buses come in an interval of only 10~15 minutes, the route with the best accessibility is this route.

Yeongsil Trail

The Yeongsil Trail is connected to the Gwaneumsa Trail by road number 1100. This makes the transportation information really similar. Actually, the way of public transportation is same. But the time to come and go is quite different since these two trails are 30 minutes away by car. From Jeju city hall to the Yeongsil Information Center, it takes about 50 minutes. From Jungmun to Yeongsil Information Center, it takes about 30 minutes.

Donnaeko Trail

To go to Donnaeko Trail by car, you should use road number 1115 which connects Jeju city Araun mountain river, Tamra education center, and Chunwangsa temple. From Jeju city hall to Donnaeko Information Center, it takes about 60 minutes and from Seogwipo city hall, it takes about 25 minutes. If you want to use public transportation, ride Seogwipo city bus 610-1. This bus goes to the mourning gallery (, which is the entrance) only 6 times a day. It takes about 40~50 minutes on foot.

Gallery

File:Hallasan,Jeju.jpg, Hallasan seen from a distance File:Halla01.JPG, Crater lake at the top of the mountain (06/2008) File:Halla07.JPG, A view at the top (06/2008) File:Halla02.JPG, A surging crowd at the top of the mountain (06/2008) File:Halla05.JPG, At the middle of the Seongpanak trail (02/2008) File:Halla06.JPG, Lateral volcanoes of the mountain (06/2008) File:Halla04.JPG, A view on the Gwaneumsa trail (06/2008) File:Halla08.JPG, A monument at the gate of the Seonphanak trail (06/2008) File:Winter Hallasan Summit.jpg, Hallasan and its summit weather station covered with windswept ice on a cold November afternoon, overlooking the Yellow Sea File:Hallasan from plane.jpg, Hallasan seen from a plane

Notes

References

*
Halla-san Official website
{{Authority control Polygenetic shield volcanoes Volcanoes of South Korea Volcanoes of the Pacific Ocean Volcanic crater lakes Mountains of Jeju Province Pliocene shield volcanoes Pleistocene shield volcanoes Dormant volcanoes Jeju City Seogwipo Mountains of South Korea One-thousanders of South Korea Highest points of countries Shield volcanoes of Asia Sacred mountains of South Korea