Given the large number of active volcanoes worldwide, it's highly likely that one of them is still erupting. Some volcanic eruptions are more widely known due to their intensity or impact, while others may go unnoticed. It's in these more recognized or mentioned volcanic eruptions that the mistake is often made of referring to magma and lava as the same thing, even though they are not. There are numerous differences between magma and lava, which we will examine in detail.
For this reason, we are going to dedicate this article to telling you what the main differences between magma and lava are and their main characteristics.
what is magma
Let's start this article by understanding what magma is. Magma is simply defined as the molten rock from the center of the Earth. As a result of fusion, magma is a mixture of liquid substances, volatile compounds and solid particles.
The composition of the magma itself is difficult to define because it depends on factors such as temperature, pressure, minerals, etc., but in general, we can distinguish two types of magma based on the mineral composition. Let's take a look here:
- mafic magma: It contains a proportion of silicates, in the form of silicates rich in iron and magnesium, generally created by the melting of the thick crust of the seabed. For its part, this type of magma is also called basal magma, which is characterized by having a fluid appearance due to its low silica content. As for its temperature, it is usually between 900 ÂşC and 1.200 ÂşC.
- Felsic magmas: Compared to the former, they are magmas that contain a lot of silica, in the form of silicates rich in sodium and potassium. They usually have their origin in the melting of the continental crust. They are also called acid magma and, due to their high silica content, they are sticky and do not flow well. As for the temperature of the felsic magma, it is usually between 650°C and 800°C.
It can be seen that both types of magma have high temperature. However, when the magma cools, it crystallizes, creating igneous rocks. These can be of two types:
- Plutonic or intrusive rock when magma crystallizes inside the Earth.
- A volcanic or overflow rock It forms when magma crystallizes on the Earth's surface.
However, magma remains inside a volcano in a structure called a magma chamber, which is simply an underground cavern that stores large quantities of lava and is the deepest point of a volcano. The depth of the magma chamber is difficult to determine, or even to detect. However, magma chambers have been discovered at depths of between 1 and 10 kilometers. Finally, when magma manages to rise from the magma chamber through the volcano's conduits or vents, a volcanic eruption occurs.
what is lava
After learning more about magma, we can move on to discussing what lava is. Lava is simply magma that reaches the Earth's surface in volcanic eruptions and produces what we know as lava flows. Ultimately, lava is what we see in volcanic eruptions.
Its characteristics, both the composition of the lava and its temperature, depend on the specificity of the magma, although the temperature of lava varies throughout its journey across the Earth's surface. In particular, lava is exposed to two factors that magma is not: atmospheric pressure, which is responsible for releasing all the gases present in the magma, and ambient temperature, which causes the lava to cool rapidly and produce volcanic or overflow rocks. When lava reaches the surface, it can be found in different forms and compositions, which vary depending on its origin.
What are the differences between magma and lava
If you've made it this far, you may have noticed the difference between magma and lava. In any case, here we will briefly summarize their main differences to clarify possible doubts. So when you're wondering if it's magma or lava, keep the following in mind:
- Location: this is probably the biggest difference between magma and lava. Magma is lava below the surface and lava is magma that rises and reaches the surface.
- Exposure to factors: Specifically, lava is exposed to factors typical of the earth's surface, such as atmospheric pressure and ambient temperature. In contrast, the magma below the surface is not affected by these factors.
- Rock Formation: When magma cools, it cools slowly and deeply, creating plutonic or intrusive rocks. Conversely, when lava cools, it cools rapidly and at the surface, forming volcanic or overflow rocks. For a more in-depth analysis of how volcanic rocks form, you can consult other related resources.
Parts of a volcano
These are the parts that make up the volcanic structure:
Crater
It is the opening at the top where lava, ash, and all pyroclastic material are ejected. When we talk about pyroclastic materials, we are referring to all fragments of volcanic igneous rocks, crystals of different minerals , etc. There are many craters of various sizes and shapes, but the most common are round and wide. Some volcanoes have more than one crater.
Some parts of the volcano are responsible for strong volcanic eruptions. These eruptions also produce some volcanic eruptions strong enough to destroy or modify parts of the volcano's structures. During these eruptions, interesting phenomena can be observed that highlight the dynamics of magma and lava.
Caldera
It's one of the parts of a volcano that is often confused with the crater. However, when a volcano releases almost all the material from its magma chamber in an eruption, a huge depression forms . Craters have created instability in active volcanoes that lack structural support. The lack of structure within the volcano caused the ground to collapse inward. The size of this crater is much larger than the caldera. Remember that not all volcanoes have a caldera.
Volcanic cone
It is an accumulation of lava that solidifies as it cools. All extravolcanic pyroclasts produced by volcanic eruptions or explosions over time also form part of the volcanic cone. Depending on the number of eruptions it has experienced, the thickness and size of the cones can vary. The most common volcanic cones are cinder cones, spatter cones, and tuff cones. For a more detailed analysis of the ecological impact of volcanoes, you can consult specific studies.
cracks
These are fissures that occur in the area where magma is being expelled. They are fissures or elongated cracks that provide ventilation to the interior and occur in areas where magma and internal gases are expelled to the surface. In some cases, this causes an explosive release through conduits or vents, while in others, it is released peacefully through cracks that extend in all directions and cover large areas of land.
Chimneys and dikes
Volcanic vents are conduits that connect the magma chamber to the crater. This is where the volcano erupts lava. Additionally, gases released during the eruption travel through the vent. One aspect of volcanic eruptions is pressure. Considering the pressure and the amount of material that rises through the vent, we can see that rock is torn away by the pressure and expelled from the vent. Furthermore, the study of submarine volcanoes and their ecological impact becomes crucial for a better understanding of these phenomena.
As for the dikes, they are igneous or magmatic formations with tubular shapes. They pass through adjacent layers of rock and then solidify as the temperature drops. These dikes are created when magma rises in new fissures or fissures to travel along paths in the rock. Pass through sedimentary, metamorphic, and plutonic rocks along the way.
I hope that with this information you can learn more about the main differences between magma and lava.
