After the Elephant Trunk Rock broke and fell into the sea, how many other landscapes are "trembling"?

On the afternoon of December 16, 2023, accompanied by a loud "boom", the Elephant Trunk Rock next to Shen'ao Fishing Port in New Taipei City, Taiwan Province, my country suddenly broke, and this incident attracted widespread attention from the society. Many people have not had time to see it, but now it has suddenly collapsed, and the "elephant trunk" has fallen into the sea, leaving only the "elephant body", which is very regrettable. What is so special about the Elephant Trunk Rock? Why did it suddenly collapse? Will some other similar landscapes on the earth suffer the same fate?

Elephant Trunk Rock next to Shen'ao Fishing Port (copyright image of the photo library, reprinting and use may cause copyright disputes)

Comparison of the Elephant Trunk Stone before and after it broke (Source: Screenshot of Shuo Tianxia video)

01 The coastal wonders that have fallen in recent years

Elephant Trunk Rock is a famous landmark in New Taipei City. It is named for its unique shape that resembles an elephant drinking water at the seaside, attracting a large number of tourists. Geological experts found that this is a natural landscape formed by coastal erosion. The surface of the rock is covered with joints and cracks, and the surging waves below keep hitting the "elephant trunk". Local staff were worried about danger and set up warning signs next to it many years ago to remind tourists not to climb. However, some tourists still ignored the dissuasion and climbed to the top of the rock and trampled on it mercilessly in order to take cool photos. A geology professor once estimated four years ago that Elephant Trunk Rock would stand for a thousand years. Unexpectedly, just four years later, it collapsed due to long-term weathering, waves and tourists' wanton trampling.

There are many geological wonders on the earth similar to the Elephant Trunk Rock, and they have the same fate. In the process of fighting against the waves, the hard rocks are always at a disadvantage. As long as there is enough time, they will eventually be eroded into all kinds of strange shapes, and some have even collapsed completely.

The London Arch, a natural double-arch bridge on the coastline of Port Campbell National Park in Victoria, Australia, collapsed in January 1990; at the end of a cliff on the island of Gozo, Malta, an island country in the central Mediterranean, there is a scenic spot called "Blue Window"-a naturally formed limestone arch that disappeared forever in a storm in March 2017; next to Darwin Island in the Galapagos Islands on the west coast of South America, the tall "Welcome Gate" formed by volcanic basalt collapsed in May 2021; the famous "Stone Old Man" in Qingdao, Shandong also collapsed after a storm in October 2022.

The amazing sight of the "Stone Old Man" crossing the sun in Qingdao, Shandong (copyright image of the photo library, reprinting and use may cause copyright disputes)

Comparison of Shilaoren before and after the collapse (Source: Screenshot of Good Morning Shandong video)

Geological phenomena tell us that “seas run dry and rocks crumble” is not a reliable oath. There really is “seas run dry” that can turn the sea into mulberry fields, and there really is “rocks crumble” that can change beyond recognition.

02 The past and present of the sea-eroded arch bridge

The so-called Elephant Trunk Rock is actually a natural arch. Ancient people saw the strange shape of this natural rock mass that spans the valley or river and named it "Fairy Bridge". Some people saw that it was shaky but still stood firm and praised it as "a strong bridge".

Different natural arches have slightly different causes of formation. Some are formed by water erosion, some by seawater erosion, and some by wind erosion . The natural arches that have been discovered so far are mainly concentrated in the sandstone distribution area of ​​the Colorado Plateau in the southwestern United States. There are also many natural arches in China, mainly concentrated in the limestone distribution area and sandstone distribution area in the west and south, such as Fengshan County, Guangxi, Liping County, Guizhou, Wulong County, Chongqing, Zhangjiajie, Hunan, Danxia Mountain, Guangdong, Longhu Mountain, Jiangxi , etc. In addition, they are often found near some coasts, which are called sea erosion arch bridges (or sea domes) .

Natural arches have important tourism value . From them, we can not only see the magical power of nature, but also feel the changes of the earth. There is a famous scenic spot called "Dinosaur Exploring the Sea" in Jinshitan National Geopark, Dalian, Liaoning. When the tide rises, it looks like a huge dinosaur poking its head into the sea from a distance; when the tide recedes, it looks like a dinosaur sucking the sea water dry. In fact, it is the remnant of a cape . The so-called cape is a pointed land extending into the ocean, which is common at the front end of the peninsula and is formed by violent sea erosion . In the sea-land junction area, the sea water continues to beat and impact the land, causing the land to retreat continuously and the ocean to advance continuously, which will slowly form a variety of sea erosion landforms. For example, steep cliffs are called sea cliffs ; rock pillars formed by collapse are called sea pillars ; sea caves formed by hollowing out hard cliffs, when the two sides of the sea cave continue to be eroded by waves and finally penetrate each other, forming a sea arch bridge .

Dalian Golden Stone Beach "Dinosaurs Exploring the Sea" (copyright image from the photo library; reprinting and use may cause copyright disputes)

The formation process of sea erosion arch bridges makes us deeply feel the infinite power of sea water. It is the ocean that created them, and it will eventually be destroyed by the ocean. As long as the tides and waves of the ocean never stop, the silent changes of sea and land will have a beginning and no end, and new coastal erosion landforms will gradually form.

03 The hazards of coastal erosion

In the eyes of many people, sea erosion landforms are often charming and beautiful scenery, but for coastal land and engineering facilities such as houses and roads, coastal erosion is a serious geological disaster . On the one hand, coastal erosion will cause a certain loss of coastal land area ; on the other hand, it may also endanger the safety of ports and buildings . Studies have found that among various types of coasts, sandy coasts are the most susceptible to erosion, followed by muddy coasts, and bedrock coasts have the strongest ability to resist erosion . There are many factors that cause coastal erosion, mainly including the beating, impact and erosion of the coast by wind and waves, tides, tsunamis, etc.

Sea Tide (copyright image from the gallery, reprinting may cause copyright disputes)

Although the propagation direction of wind and waves is unpredictable, they are present all the time and can cause severe erosion to the coast.

Ocean tides are the rise and fall of sea water caused by the tidal force of celestial bodies. Day after day, the destructive power exists for a long time. Sometimes, the rise and fall of sea levels caused by changes in meteorological factors such as wind, air pressure, precipitation, freezing and melting ice (the so-called meteorological tide) can also cause coastal collapse.

Tsunamis are huge waves caused by undersea earthquakes, undersea volcanic eruptions and major storms. When they gradually approach the coast, energy will continue to accumulate, instantly forming a huge wall of water, which will pour out all at once and cause huge damage to the coast.

In addition, global sea level rise has also accelerated coastal erosion . Rising sea levels will lead to increased near-shore wave and tidal energy, stronger storm surges, and more severe damage to the coast.

Storm surge (copyrighted image from the gallery; reprinting may lead to copyright disputes)

Coastal erosion is mainly mechanical erosion, but sometimes chemical erosion should not be underestimated. In East Sussex, southern England, close to the English Channel, there is a famous "Seven Sisters Cliffs", named after the seven magnificent white cliffs connected together. The entire coast is composed of chalk, and it is pure white as far as the eye can see. However, chalk is a loose soil-like limestone, the main chemical component of which is calcium carbonate, which is easily dissolved and destroyed by seawater. Under the action of erosion over the years, the bottom of the chalk cliff gradually expanded from the initial groove to a sea cave, and finally collapsed to form a steep cliff.

Seven Sisters Cliffs and Belle Tot Lighthouse (copyright image from the gallery, reprinting may cause copyright disputes)

On this cliff stands an old lighthouse called "Belle Toth". It was built in 1832. The tower is about 14 meters high and weighs 850 tons. The tower is made entirely of hard granite. It took more than two years to complete and put into use. Strangely, since the lighthouse was built, it has been getting closer and closer to the edge of the cliff on the coast. At the closest point, it was only 3.5 meters away, which put it in danger of falling and collapsing at any time. So people moved it back 17 meters in 1999. However, people originally expected that the relocation of the lighthouse would at least ensure its safety for the next 50 years. But just over 20 years later, people began to worry about it again, and a new relocation plan was put on the agenda.

04 How to stop coastal erosion

Coastal erosion has caused many disasters to mankind in history, and many coastal countries and regions have suffered greatly from it. In the Middle Ages in England, there was a prosperous port city called Dunwich. From 1286 to 1362, several storm surges hit the coast of Dunwich, destroying a large number of buildings, flooding large areas of land, and eventually completely destroying it.

Dunwich Beach in the UK today (copyright image from the gallery, reprinting may cause copyright disputes)

Today, the east coast of the UK is swallowed up by the sea by one meter every year, and some seaside homes are threatened, and some residents are even forced to evacuate. According to media reports, the coast between San Francisco and Half Moon Bay in California, USA, is constantly eroding, and many apartments near the edge of the coast may fall into the Pacific Ocean at any time; a seaside community in New South Wales, Australia is threatened by coastal erosion, causing the luxury houses built on the seaside cliffs to become dangerous buildings. Some islands in the ocean are even more dangerous. For example, Easter Island in Chile faces the dual threats of rising sea levels and coastal erosion. Archaeologists plan to build breakwaters on the local coast to protect the world heritage here from being swallowed by the sea.

Easter Island (copyrighted image from the gallery; reprinting may lead to copyright disputes)

Unlike sudden geological disasters such as collapse, landslide, and mudslide, coastal erosion occurs and develops slowly, and is formed gradually and progressively. It is a slow-changing geological disaster that usually does not cause casualties, but often seriously damages natural resources and the ecological environment. People can monitor and predict its future development trends, and then take preventive and control measures.

There are many ways to prevent coastal erosion. First, we must maintain the amount of water and sediment carried by rivers into the sea, especially in the estuary delta area. In recent years, due to the rise in sea levels and the intensification of sediment loss, the delta plain has insufficient ability to retain sediment. Some scholars believe that by 2100, the rise in sea levels may cause the area of ​​some deltas to disappear by more than 80%. We must find ways to keep the amount of sediment brought by rivers greater than the amount of loss in order to save the delta from crisis.

Breakwater of Qingdao Olympic Sailing Center (copyright image of the gallery, reprinting may cause copyright disputes)

Secondly, we should actively carry out coastal ecological protection and restoration work, and carry out artificial shore protection through some engineering measures and biological measures, such as building breakwaters, underwater sand dams, and vegetation restoration. The culprit for coastal erosion disasters is not only seawater, but also human engineering activities such as quarrying and sand excavation. Artificial destruction will significantly increase the speed of coastal erosion. Therefore, unreasonable quarrying and sand excavation and shore destruction should also be strictly prohibited. Only by living in harmony with the ocean can we better develop the ocean, protect resources, and resist disasters.

Author: Ma Zhifei, a popular science writer and member of the Beijing Science Writers Association, has written more than 10 popular science books, including "A Dream of Red Mansions" and "Glass Earth". He has won the Ministry of Natural Resources' Excellent Popular Science Book Award, the Wu Dayou Popular Science Book Award, and the China Natural Resources Writers Association's "China Gem Literature Award" Popular Science Works Award.

Reviewer: Dong Hanwen, Associate Researcher, Institute of Geology, Chinese Academy of Geological Sciences

Produced by: Science Popularization China

Produced by: China Science and Technology Press Co., Ltd., China Science and Technology Publishing House (Beijing) Digital Media Co., Ltd.