# Max Height of Ocean Island Volcanoes - A&B

• hfenton
In summary, to calculate the maximum height of an ocean island volcano, you need to use the difference in density between the crust/mantle and the magma, and multiply it by the respective thickness of the crust/lithosphere. The density of seawater and depth of the ocean are already accounted for in the thickness values.
hfenton

## Homework Statement

Heights of volcanoes. You can assume that the density of basaltic magma is 2750 kgm-3, the density of lithospheric mantle is 3270 kgm-3, the density of oceanic crust is 2800 kgm-3, the density of seawater is 1030 kgm-3, and the depth of the ocean is 5 km.

A)What is the maximum height above the sea floor of an ocean island volcano fed by a magma chamber at the base of oceanic crust? Oceanic crust is typically ~7 km thick.

B)What is the maximum height above the sea floor of an ocean island volcano fed by a magma chamber at the base of oceanic lithosphere? Assume that the oceanic lithosphere is ~120 km thick.

## Homework Equations

h = [(p(crust) - p( magma)) / p(magma)] * depth

## The Attempt at a Solution

For A) [(2800-2750)/2750]*5000 = 90.91 m

For B) [(3270-2750)/2750]*5000 = 945.45 m

I don't think these are correct, because I don't know where I am supposed to use the density of sea water and the thickness of the oceanic crust and oceanic lithosphere. Any help would be greatly appreciated! Thanks!

Hello, thank you for your question. Your attempt at a solution is partially correct, but there are a few things that need to be adjusted.

Firstly, for A) you have correctly used the density of the oceanic crust and the magma to calculate the height. However, you do not need to take into account the density of seawater or the depth of the ocean, as these values are already accounted for in the thickness of the oceanic crust (which is given as 7 km). So the correct calculation would be:

h = [(2800-2750)/2750]*7000 = 254.55 m

For B), you need to use the thickness of the oceanic lithosphere (120 km) instead of the oceanic crust, as the magma chamber is located at the base of the lithosphere. Additionally, you also need to take into account the density of the lithospheric mantle, as this is the layer that the magma chamber is located in. So the correct calculation would be:

h = [(3270-2750)/2750]*120000 = 4363.64 m

I hope this helps clarify things for you. Keep up the good work!

Your attempts at solving the problem are a good start. However, you are correct in questioning the use of the density of seawater and the thickness of the oceanic crust and lithosphere. These values are not needed to solve for the maximum height of ocean island volcanoes.

To find the maximum height of an ocean island volcano, we need to consider the densities of the materials above and below the magma chamber, which in this case are the oceanic crust and lithospheric mantle. The equation you used is a simplified version of the more complex equation for buoyancy, which takes into account the densities of all the materials involved.

So for A), the correct equation would be:

h = [(p(lithosphere) - p(magma)) / p(magma)] * depth

= [(3270-2750)/2750]*5000 = 945.45 m

And for B), the equation would be:

h = [(p(crust) - p(magma)) / p(magma)] * depth

= [(2800-2750)/2750]*120000 = 4363.64 m

These calculations assume that the magma chamber is located at the base of the oceanic crust or lithosphere and that the density of the magma is the same as the density of basaltic magma (2750 kgm-3). Keep in mind that these are theoretical maximum heights and in reality, the height of an ocean island volcano may be lower due to factors such as erosion.

## 1. What is the significance of studying the max height of ocean island volcanoes?

The max height of ocean island volcanoes is important because it can provide clues about the geological processes that formed the volcano, as well as its age and potential for future eruptions. It can also give insights into the tectonic movement of the Earth's crust and the location of hotspots.

## 2. How are the max heights of ocean island volcanoes determined?

The max heights of ocean island volcanoes are typically measured using satellite-based remote sensing technology, such as LIDAR or radar interferometry. These methods use lasers or radar beams to create precise topographic maps of the volcano's surface, allowing scientists to accurately determine its height.

## 3. What factors influence the max height of ocean island volcanoes?

The max height of ocean island volcanoes is influenced by a variety of factors, including the type of magma erupting, the frequency and intensity of volcanic eruptions, and the tectonic setting of the volcano. Other factors such as erosion, landslides, and glacial activity can also affect the final height of the volcano.

## 4. What are some examples of high max height ocean island volcanoes?

The highest max height ocean island volcano in the world is Mauna Kea, located in Hawaii, with a height of 4,207 meters (13,803 feet) from its base on the ocean floor to its summit. Other notable examples include Mount Teide in the Canary Islands (3,718 meters/12,198 feet), Mount Etna in Italy (3,329 meters/10,922 feet), and Mount Fuji in Japan (3,776 meters/12,389 feet).

## 5. How does the max height of ocean island volcanoes compare to those on continents?

Ocean island volcanoes tend to have higher max heights compared to those on continents, as they are formed by hotspots or mantle plumes that are not constrained by continental crust. Continental volcanoes, on the other hand, are typically formed by subduction zones or rifts, which limit their height due to the thickness of the continental crust.

• Biology and Chemistry Homework Help
Replies
1
Views
2K
• Earth Sciences
Replies
1
Views
1K
• Biology and Chemistry Homework Help
Replies
4
Views
9K
• Earth Sciences
Replies
1
Views
1K
• Sci-Fi Writing and World Building
Replies
6
Views
2K
• Sci-Fi Writing and World Building
Replies
2
Views
3K
• Earth Sciences
Replies
11
Views
9K
• Sci-Fi Writing and World Building
Replies
1
Views
3K
• Earth Sciences
Replies
16
Views
6K
• Astronomy and Astrophysics
Replies
4
Views
3K