Epeirogenic motion is the movement of the Earth’s crust which is relatively slow and occurs over a long period of time and covers a large area. Epeirogenic motion can cause the surface of the Earth to move vertically, both up and down, resulting in changes in shape seen on land. Epeirogenic motion is also referred to as continental formation. (Also read: 8 Processes of Continents and Ocean Formation). Epeirogenic motion is part of a tectonic Earthquake. Epeirogenic movements are divided into two types, namely:
- Positive Epeirogenic Motion
A positive epeirogenic movement is the movement of shifting which results in the descent of the land or layers of the Earth’s crust. This movement is characterized by an increase in sea level which causes the coastline to move to the mainland because the land has decreased. Examples of events caused by positive epeirogenic motion:
- Epeirogenic movements that occur in eastern Indonesia, from the southwest Maluku islands to the island of Banda.
- Epeirogenic movements occur in the Maluku islands which have a geographical location with a total area of 712,479.6 km2, consisting of 92.4% of the ocean with an area of 658,294.69 km2, whereas the remaining 7.6% is land with an area of 54,185 km2. In other words, most Maluku islands are the sea.
- Banda Island is part of the Maluku islands, has an area of 180 km2. Epeirogenic movements also occur on the island of Banda.
- The fall of the Hudson River estuary in America is seen up to 1,700 meters. The Hudson River is a 507 km long river that flows from north to south across the eastern region of New York. The Hudson River empties into the Upper New York Bay.
- The fall of the Congo River valley in western Central Africa which reaches 2,000 km below sea level. The Congo River is the second longest river after the Nile, 4,700 km long.
- The sinking of the Gondwana continent. Gondwana is a giant continent in the southern hemisphere which is a vast land that had existed around 500 to 180 million years ago. Positive epeirogenic movements were thought to be the cause of the Gondwana continent to be an Indian Fault.
- Precipitation that occurs at the mouth of the Mississippi River is caused by positive epeirogenic motion which results in the geosynclinals region being covered by deposits. The Mississippi River is the longest river in America, with a length of 3,734 km2. The Mississippi River empties into the Gulf of Mexico.
- Negative Epeirogenic Motion
Negative epeirogenic motion is a shifting motion which results in the rise of land or layers of the Earth’s crust. This motion is characterized by an increase in land, resulting in the sea surface as if seen to be falling. Examples of events caused by negative epeirogenic motion:
- Natural phenomena due to the presence of negative epeirogenic movements in Indonesia occur on the island of Timor and the island of Buton.
- The island of Timor is divided between independent countries of East Timor and West Timor which are part of the province of East Nusa Tenggara and have an area of 30,777 km2.
- Buton Island is an island in Southeast Sulawesi, with an area of 4,408 km2.
- The rise of the Colorado plateau is also caused by negative epeirogenic motion. The Colorado Plateau, United States has an area of 337,000 km2.
- Up the northern part of Simeulue Island. Simeulue Island is an island located in West Sumatra, has an area of 2,310 km2 with an altitude of 567 m. The rise of the northern part of the island of Simeulue is caused by epeirogenic motion. This phenomenon occurred to coincide with the occurrence of the Tsunami disaster in Aceh in the year of 2004.
- Epeirogenic negative movements also cause the Stockholm coast to rise 1 meter every 100 years.
Besides causing changes in shape on the surface of the Earth, epeirogenic motion also affects creatures that live on Earth.
- Bring the Water Sources Closer
The occurrence of a positive epeirogenic motion results in water rising to the surface. Water is the main substance that is needed by living things on Earth. With positive epicenter motion, water sources that are far below the Earth can be pushed up to the surface of the Earth. (Also read: 6 Differences in Territorial Sea and High Sea Based on Comprehension).
- A New Place of Life for Organisms
The occurrence of negative epeirogenic movements causes land to rise which then forms mountains or hills that can be overgrown with plants and become a place of life for animals.
- Agricultural or Plantation Area
The formation of highlands can be utilized by humans for plantation and agricultural areas. (Also read: 13 Effects of Ocean Water as An Irrigation Supplement).
- Tourist Attraction
The formation of new mountains with fresh air and beautiful scenery can be used for tourist attractions. (Also read: 10 Ways to Preserve the Sea and the Beach for the Earth).
The negative impact caused by epeirogenic motion, called natural disasters. You can also learn about the biosphere as the skin layer of the Earth.
Landslides often occur in mountainous areas. Landslides are land movement events that occur due to periods of rock or soil of various types, such as the fall of rocks or large lumps of soil. Landslides occur due to several, one of which is a trigger factor such as the movement of material by the soil.
The formation of steep slopes tends to cause erosion. Erosion is the process of eroding rocks, soil, and other solids caused by movements of water, ice, or wind.
Shifting the surface of the Earth can also cause Earthquakes. Earthquakes are vibrations that occur on the surface of the Earth due to the sudden release of allergies that create waves as dynamic. Earthquakes that occur due to epicrogenic motion are included in ordinary Earthquakes or minor Earthquakes which are only caused by the movement of crust.
So, that is the understanding of epeirogenic motion which is worthy of us to know and learn. Hopefully this new knowledge can be useful for you. (Also read: 17 Importance of Ocean Resource Management).