World's Deepest: Surface Depressions, Holes, Caves

[Mighty_Emperor]

No jokes at the back please!!

Explorers find world's deepest hole

Tuesday, August 10, 2004 Posted: 0015 GMT (0815 HKT)


ZAGREB, Croatia (AP) -- Cave explorers discovered a pit inside a mountain range in central Croatia believed to have the world's deepest subterranean vertical drop, at nearly 1,700 feet, a scientific institute reported Monday.

The cave, in Croatia's mountainous Velebit region, has a steady, weaving descent of 203 feet before it takes a direct vertical plunge of 1,693 feet through the ground, said Ana Sutlovic Baksic, a researcher at the Velebit Speleological Society.

The cave's widest stretch is about 100 feet.

"We have even bigger caves in Croatia, but according to available data, this cave has the world's deepest vertical drop," Sutlovic Baksic said.

At the foot of the Velebit cave are small ponds and streams, including one of the largest known colonies of subterranean leeches, Sutlovic Baksic said.

It is located in the Rozanski Hip National Park reserve in the rocky Velebit mountain range in central Croatia. The pit was discovered by a team of explorers from around the country.

The Voronya Cave in Georgia's West Caucasus has the world's deepest cavern, measuring 5,610 feet. But the pit discovered in Croatia is thought to have the largest underground vertical drop.

Croatia, which is rich in natural wonders, is home to two of the world's 20 deepest caves.

The Velebit region is Croatia's largest mountain range, attracting speleologists, botanists and hikers from around the world. Much of the rugged area remains untouched, and scientific expeditions over its vast expanse covered by rare flora and fauna have been ongoing for years.

http://edition.cnn.com/2004/TECH/science/08/09/croatia.deep.cavern.ap/index.html

 

[Mighty_Emperor]

That might be the deepest cave but this is the deepest hole:

Hole Drilled to Bottom of Earth's Crust, Breakthrough to Mantle Looms

By Robert Roy Britt
LiveScience Senior Writer
posted: 07 April 2005
08:51 am ET


Seeking the elusive 'Moho'

Scientist said this week they had drilled into the lower section of Earth's crust for the first time and were poised to break through to the mantle in coming years.

The Integrated Ocean Drilling Program (IODP) seeks the elusive "Moho," a boundary formally known as the Mohorovicic discontinuity. It marks the division between Earth's brittle outer crust and the hotter, softer mantle.

The depth of the Moho varies. This latest effort, which drilled 4,644 feet (1,416 meters) below the ocean seafloor, appears to have been 1,000 feet off to the side of where it needed to be to pierce the Moho, according to one reading of seismic data used to map the crust's varying thickness.

The new hole, which took nearly eight weeks to drill, is the third deepest ever made into the floor of the sea, according to the National Science Foundation (NSF). The rock collection brought back to the surface is providing new information about the planet's composition.

"It will provide important clues on how ocean crust forms," said Rodey Batiza, NSF program director for ocean drilling.

Already the types of rocks recovered show that conventional interpretation of Earth's evolution are "oversimplifying many of the features of the ocean’s crust," said expedition leader Jay Miller of Texas A&M University. "Each time we drill a hole, we learn that Earth’s structure is more complex. Our understanding of how the Earth evolved is changing accordingly."

The latest drilling was done at the Atlantis Massif, located at the intersection of the Mid-Atlantic Ridge and the Atlantis fracture zone, two plates of the planet's broken crust. The seafloor is shallower at the center of this region and therefore easier to reach.

It's not clear yet whether drilling should continue at the new hole or if another one should be started in the effort the reach the mantle. Such work isn't likely to begin again in the next year, said Barbara John, a University of Wyoming geologist and one of the co-chief scientists on the expedition.

"We need to evaluate all the data we have from the cruise and re-analyze the seismic data, to determine whether it's better to deepen the current hole or drill elsewhere, or maybe even collect additional seismic data to better constrain where to drill," John told LiveScience. "Our major result is that we've recovered the lower crust for the first time and have confirmed that the Earth's crust at this locality is more complicated than we thought."

John said mantle material will be evident when and if it's brought up because it will have different texture and chemistry and will contain different proportions of minerals compared with rock in the crust.

Drillers use the vessel JOIDES Resolution. The 10-year, $1.5 billion program is funded by the NSF and Japan's Ministry of Education, Culture, Sports, Science, and Technology.

Source

Lord save us for surely Hell itself will come apouring out!!!

 

[punychicken]

Hole Drilled to Bottom of Earth's Crust

Story

Scientist said this week they had drilled into the lower section of Earth's crust for the first time and were poised to break through to the mantle in coming years.

The Integrated Ocean Drilling Program (IODP) seeks the elusive "Moho," a boundary formally known as the Mohorovicic discontinuity. It marks the division between Earth's brittle outer crust and the hotter, softer mantle.

The depth of the Moho varies. This latest effort, which drilled 4,644 feet (1,416 meters) below the ocean seafloor, appears to have been 1,000 feet off to the side of where it needed to be to pierce the Moho, according to one reading of seismic data used to map the crust's varying thickness.

The new hole, which took nearly eight weeks to drill, is the third deepest ever made into the floor of the sea, according to the National Science Foundation (NSF). The rock collection brought back to the surface is providing new information about the planet's composition.

"It will provide important clues on how ocean crust forms," said Rodey Batiza, NSF program director for ocean drilling.

Already the types of rocks recovered show that conventional interpretation of Earth's evolution are "oversimplifying many of the features of the ocean’s crust," said expedition leader Jay Miller of Texas A&M University. "Each time we drill a hole, we learn that Earth’s structure is more complex. Our understanding of how the Earth evolved is changing accordingly."

The latest drilling was done at the Atlantis Massif, located at the intersection of the Mid-Atlantic Ridge and the Atlantis fracture zone, two plates of the planet's broken crust. The seafloor is shallower at the center of this region and therefore easier to reach.

It's not clear yet whether drilling should continue at the new hole or if another one should be started in the effort the reach the mantle. Such work isn't likely to begin again in the next year, said Barbara John, a University of Wyoming geologist and one of the co-chief scientists on the expedition.

"We need to evaluate all the data we have from the cruise and re-analyze the seismic data, to determine whether it's better to deepen the current hole or drill elsewhere, or maybe even collect additional seismic data to better constrain where to drill," John told LiveScience. "Our major result is that we've recovered the lower crust for the first time and have confirmed that the Earth's crust at this locality is more complicated than we thought."

John said mantle material will be evident when and if it's brought up because it will have different texture and chemistry and will contain different proportions of minerals compared with rock in the crust.

Drillers use the vessel JOIDES Resolution. The 10-year, $1.5 billion program is funded by the NSF and Japan's Ministry of Education, Culture, Sports, Science, and Technology.

The Earth’s radius is about 4,000 miles (6,400 kilometers). The main layers of its interior are in descending order: crust, mantle and core.

The crust thickness averages about 18 miles (30 kilometers) under the continents, but is only about 3 miles (5 kilometers) under the oceans. It is light and brittle and can break. In fact it's fractured into more than a dozen major plates and several minor ones. It is where most earthquakes originate.

The mantle is more flexible – it flows instead of fractures. It extends down to about 1,800 miles (2,900 kilometers) below the surface.

The core consists of a solid inner core and a fluid outer core. The fluid contains iron, which, as it moves, generates the Earth’s magnetic field. The crust and upper mantle form the lithosphere, which is broken up into several plates that float on top of the hot molten mantle below.

 

[Anonymous]

4,000 holes in Blackburn, Lancashire.

 

[Rubyait]

yeah apparently the news was rather sad, they had to count them all...

 

[Timble2]

...and now they know how many holes it takes to fill the Albert Hall....

On thread, I wonder how long it'll be before someone claims that it's this drilling that's responsible for the recent spate of Earthquakes.

BTW I thought I remembered a Mohole project from the early 60s (probably featured in Look and Learn or The Meccano Magazine)

Project Mohole

 

[Human_84]

Coulda swore my roomies stomach was the deepest hole...

 

[EnolaGaia]

Results from the long-running BedMachine project in Antarctica indicate the deepest surface point on land (i.e., not covered by an ocean) is a canyon beneath the Denman Glacier. Researchers calculate the canyon's base level is on the order of 3,500m (11,500 ft) below sea level.

Denman Glacier: Deepest point on land found in Antarctica

The deepest point on continental Earth has been identified in East Antarctica, under Denman Glacier.

This ice-filled canyon reaches 3.5km (11,500ft) below sea level. Only in the ocean are the valleys deeper still.

The discovery is illustrated in a new map of the White Continent that reveals the shape of the bedrock under the ice sheet in unprecedented detail.

Its features will be critical to our understanding of how the polar south might change in the future.

For comparison, the lowest exposed land on Earth, at the Dead Sea shore, is just 413m (1,355ft) below sea level. ...

For decades, radar instruments have crisscrossed Antarctica, sending down microwave pulses to peer through the ice and trace the underlying rock topography. But there are still vast areas for which there is little or no data.

Dr Morlighem's solution has been to use some physics - mass conservation - to plug these holes.

For instance, if it's known how much ice is entering a narrow valley and how fast it's moving - the volume of that ice can be worked out, giving an insight into the depth and roughness of the hidden valley floor.

For the 20km-wide Denman Glacier, which flows towards the ocean in Queen Mary Land, this approach reveals the ice to be descending to over 3,500m below sea level.

"The trenches in the oceans are deeper, but this is the deepest canyon on land," explained Dr Morlighem.

"There have been many attempts to sound the bed of Denman, but every time they flew over the canyon - they couldn't see it in the radar data.

"The trough is so entrenched that you get side-echoes from the walls of the valley and they make it impossible to detect the reflection from the actual bed of the glacier," he told BBC News.

For comparison, the deepest ocean point - in the Mariana Trench in the western Pacific - goes to just shy of 11km below the sea surface. There are land canyons that can be described to have taller sides, such as Yarlung Tsangpo Grand Canyon in China, but their floors are above sea level. ...

FULL STORY: https://www.bbc.com/news/science-environment-50753113

 

[EnolaGaia]

... The Voronya Cave in Georgia's West Caucasus has the world's deepest cavern, measuring 5,610 feet. ...

This cavern is also known as the Krubera Cave. Further exploration, including cave-diving to the bottoms of terminal water-filled pits, has increased this cave system's maximum known depth (from the surface) at 2,197 ± 20 metres (7,208 ± 66 ft).

https://en.wikipedia.org/wiki/Krubera_Cave

However ... Voronya / Krubera Cave has been supplanted as the world's deepest by Veryovkina Cave (2,212 meters / 7,257 ft).

https://en.wikipedia.org/wiki/Veryovkina_Cave

 

[EnolaGaia]

The world's deepest known freshwater flooded cave or sinkhole is the Hranice Abyss in the Czech Republic.

https://en.wikipedia.org/wiki/Hranice_Abyss
https://www.nationalgeographic.com/...-republic/deepest-underwater-cave-discovered/

New sensing surveys indicate the Hranice Abyss may be significantly deeper than currently believed. This in turn suggests that other flooded caves / sinkholes may need to be re-evaluated using sensor surveys to determine their actual depth.

Furthermore, the survey results suggest the cave may formed from the bottom up, rather than from the top down as always presumed.

Earth's Deepest Known Freshwater Cave Goes a Lot Deeper Than Anyone Ever Realised

... Using recent geophysical surveys of this national gem, known as the Hranice Abyss, scientists have traced the remarkable system of trench-like caves roughly a kilometre down (over half a mile down).

The findings are based on numerous types of geophysical data, including measurements with a gravimeter, in addition to checking electrical conductivity and natural geomagnetic fields in Earth's subsurface.

Together, this can tell scientists the general locations of rocks, minerals, caverns, and valleys that lie below.

While it's not a perfect mapping tool, it does suggest the Hranice Abyss extends much deeper than other estimates ...

FULL STORY:
https://www.sciencealert.com/earth-...cave-is-actually-a-lot-deeper-than-we-thought

PUBLISHED RESEARCH REPORT:
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2020JF005663?af=R