HAWAIIAN RASH: HOW IT OCCURS AND CHARACTERISTICS - CULTURE VOCABULARY - 2025

A Hawaiian eruption is a type of volcanic eruption in which lava moves through the volcano relatively slowly, by volcanic standards. It gets its name due to the large number of volcanic eruptions of this nature that usually occur in Hawaii.

These types of eruptions do not only occur at the top of volcanoes, like other more common eruptions. Instead, they can occur in volcanic fissures, which are cracks through which lava flows. In most cases, Hawaiian eruptions do not involve ash of any kind and do not emit gases into the atmosphere.

How is it produced?

A Hawaiian eruption occurs primarily when there is a large concentration of basaltic magma and less than 1% dissolved water at the same location.

The smaller the amount of water found in the eruption zone, the more peaceful the flow of magma will feel towards the surface.

These types of eruptions usually occur at the access points of large volcanoes, although they can also occur in volcanic rupture zones and even in subduction zones. It all depends on the concentration of water found in the area of ​​the eruption.

characteristics

Effusiveness

Hawaiian eruptions are effusive eruptions in their entirety. Effusive eruptions are those in which lava moves fluidly from underground to the Earth's surface. In contrast to explosive eruptions, these tend to be much slower and more peaceful.

These eruptions often form channels and domes of magma on the surface after the lava solidifies. These vary in shape, thickness and length, depending on the amount of lava that flows in each eruption.

The presence of water in these eruptions makes the magma volatilely poor. This causes the fragmentation of the lava to be eliminated and it simply flows, as if it were spilling, from the interior of the volcano towards the surroundings of the eruption zone.

Basaltic magma

Basalt magma is the most common type of lava that exists on Earth. It is the only type of lava capable of moving quite fluidly after an eruption.

This is nothing more than molten rock, but with high amounts of magnesium and iron, with a fairly low composition of silicone.

When this type of lava hardens after cooling, it forms basalt; from this the name of basaltic magma is obtained. This magma is formed when certain parts of the earth's crust melt, deep in the planet's soil.

Also, during Hawaiian eruptions the lava has a fairly low viscosity. This helps it to be quite fluid.

Composition

These eruptions usually occur with a low gas content and with a high temperature in the ventilation zone of the volcano.

As a consequence of the fact that the reaction occurs in a low-violent way and there is no explosion as such, few gases are produced when the lava flows to the surface.

Similarly, lava moves slowly. This slow movement causes a large amount of lava to concentrate in the eruption zone, generating very high temperatures during the flow of magma from the subsurface to the surface.

Volcanic ash

One of the main characteristics of Hawaiian eruptions is the low amount of ash they produce. Usually, volcanic ash is formed in high-combustion eruptions, when magma is expelled. This ash consists of rock fragments and various pulverized minerals.

The specific formation of volcanic ash occurs during explosive eruptions, when the gases present in the volcano expand as a product of combustion, expelling large amounts of gas into the planet's atmosphere. The gases solidify and become small fragments that make up the ash.

As Hawaiian eruptions are very mild, ash formation is much less. In fact, its creation follows another process in effusive eruptions like the Hawaiian one. When magma comes into contact with water, the water quickly turns into steam, causing rapid fragmentation of the magma.

Once the ash comes into contact with the air, it is transported by air currents for thousands of kilometers.

The distance that ash travels in a Hawaiian eruption is also much less than in an explosive eruption, since the ash does not reach a great elevation.

Differences between Hawaiian eruption and Strombolian eruption

Strombolian eruptions, named for the Italian volcano Stromboli, are small eruptions, in which magma is released to the surface in an explosive manner. Unlike Hawaiian eruptions, magma does not flow peacefully to the surface, but rather violently initially.

In an eruption of this type, lava bombs are created that can rise hundreds of meters high. The eruptions are not as violent as a totally explosive one, but they do present a certain level of force and volume, which makes them mild explosive eruptions.

These eruptions tend to generate much more ash than Hawaiian ones, as a consequence of the force with which the lava is released. The amount of gases that are created at the time of the eruption is also much greater. The gases become bubbles within the magma, causing columns of lava to form.

Hawaiian eruptions almost always last much less than Strombolian ones. A strombolian eruption is usually slow because the system that carries the lava to the surface is not affected by the explosion, causing the process to repeat itself several times.

Hawaiian eruptions have lava fountains and rivers, while Strombolian eruptions are often characterized by a shower of lava fragments.

References

1. Basaltic Lava: Definition and Characteristics, A. Lange, (nd). Taken from study.com
2. Strombolian Eruptions, San Diego State University, (nd). Taken from geology.sdsu.com
3. Hawaiian Eruption, A dictionary of Earth Sciences, 1999. Taken from encyclopedia.com
4. Hawaiian Eruption, Wikipedia in English, 2018. Taken from wikipedia.org
5. Types of Volcanoes & Eruptions, GNS Science, (nd). Taken from gns.cri.nz