I have been curious to learn more about Midway Atoll, since I may not have an opportunity of visiting it.
I believe the United States government will someday open this beautiful place for everyone.
How deep is the water around Midway island?
The lagoon is shallow and has a maximum depth of 75 feet is found near its center.
However, the average depths are much less.
Is Midway Island Volcanic?
About 27.5 million years ago, Midway Atoll was formed as a shield volcano.
A chain of over 125 volcanoes stretches over 3,720 miles across the North Pacific Ocean formed by the Hawaiian islands.
This chain consists of two main parts, namely:
The younger Hawaiian Ridge:
This part includes:
- the Hawaiian Islands, and
- a string of volcanoes extending west-northwest through Midway Island,
The Emperor Seamounts:
The Emperor Seamounts connects to the western end of the Hawaiian Ridge and is a submarine chain of volcanoes oriented almost north-south
It is a well-known fact that this particular geologic feature has positively impacted the development of ideas concerning the history of the Pacific Ocean Basin.
It has also affected the rates and directions of motion of the large crustal plates, which make up the Earth’s surface.
There are a total of eight principal Hawaiian Islands which are located at the southeast end of the chain.
The three active volcanoes located at this southeast end are:
- Kīlauea,
- Mauna Loa, and
- Loihi Seamount
Furthermore, three dormant volcanoes are located close to the southeast end of the chain.
These volcanoes include:
- Hualālai,
- Mauna Kea, and
- Haleakalā,
Towards the west, the islands appear more eroded with only a few volcanoes rising above sea levels to the west of Kauai.
These volcanoes are considered as either coral atolls or volcanic islets.
Kure Island
In the chain, the westernmost island is known as Kure Island.
This island is located west of Midway Island.
All the bovakoes located farther west and to the north just along the Emperor Seamount chain are submarines although years ago, these volcanoes were very large sun aerial volcanoes.
As time passed, these volcanoes sank beneath the sea.
This issue was mostly as a result of their enormous weight that bends the almost rigid outer layer of the Earth.
Unlike the erosion that affected volcanoes farther east, the erosion of the western islands was far greater and recognized in the 1800s.
This means that the islands to the west are much older than those to the east.
However, many years passed before this was discovered and proven through radiometric dating techniques.
To determine the ages of the islands, the potassium-argon technique was the primary technique.
This method’s principle is to measure a small percentage of the naturally occurring potassium at a slow rate, which decays to argon.
This potassium is present in rocks and minerals and is a radioactive element.
Radioactive Decay
The result of the radioactive decay is the emission of minuscule amounts of radiation which can be naturally found everywhere.
By measuring the amount of potassium in the rock or mineral and the amount of argon produced by the radioactive decay and trapped in the rock or mineral, it is possible to calculate the period necessary for that potassium to decay to decay argon.
The time taken represents the age when the lava erupted and cooled, assuming the rock did not contain any argon when it cooled and crystallized and that the potassium or argon had not been added to or removed from the rock or mineral.
Whenever minerals in a rock alter, two things can take place:
- some of the potassium is added from groundwater to the clays which replace the original minerals
- some of the argon, which is formed by radioactive decay, is lost
These processes can affect the result leading to an age much younger than the actual eruption age of the sample of lava.
To prevent errors like this, rocks that have experienced little of this kind of alteration are recommended for analysis.
With these techniques, it has become possible to determine the ages of several volcanoes in the Hawaiian-Emperor volcanic chain.
Towards the west-northwest, there is a systematic increase in age among the principal Hawaiian Islands.
Kaua`i is about 5.0 to 5.5 million years old.
The age of the volcanoes along the Hawaiian Chain continues to increase as it moves down the west-northwest.
Midway island is about 28 million years old, and the bend between the Hawaiian and Emperor Chains is about 43 million years old.
As you move down to the north, the age of the Emperor Seamounts increases and continues to get older.
The northernmost submarine volcanoes are estimated to be about 80 million years along this area.
However, the oldest date seamount has been reported to be only 65 million years old.
Along the chain, this systematic increase in ages results from the sequential formation of volcanoes at the same location.
Since scientists believe that this area consists of bitter material inside the Earth, so this location has been a hotspot.
Regardless, the volcanoes are moved away from where they were formed through the motion of the underlying Pacific crustal plate.
Studies by scientists claim that this hotspot which contains volcanoes has remained stationary for millions of years.
Assuming that this statement is true, it simply means that the rate of motion of the crustal plate can be calculated directly from the ages of each of the volcanoes and their distance from the hotspot.
The calculated rate of the Hawaiian chain has been calculated to be approximately 10 centimeters every year.
The bend in the chain between the Hawaiian and the Emperor portions of the chain indicates a major chain in the direction of the motion of the Pacific plate, which by inference, took place 43 million years ago.
This bend is predicted to be caused by a collision of India into Eurasia, which also kickstarted the formation of the Himalayan mountain range.
Frequently Asked Questions
How deep is the water around Midway island?
Existing on a platform that rises from a depth of over 2,000 fathoms, Midway is a subcircular reef that is nearly 6 miles in diameter
Is there Freshwater on Midway island?
Among the three small islands which come together to make up the Midway island, there are no freshwater lakes or rivers over the 2 square miles of land area.
However, Midway island boasts of very fine white coral sand, which is not suitable for any agricultural purposes.
From the main Hawaiian islands, this area is over 1,000 miles away.
What is Midway island known for historically?
Midway is one of the most significant events in the history of the naval base.
