[Physics Class Notes] on Lava – Volcanic Ejecta Pdf for Exam

Our planet earth contains Volcanoes. The magma is present in the form of the crust. However, the volcanic eruption allows hot gases, molten lava, and some rock fragments.

All of them collaged to form an opening gate for the volcanic path. The volcanos are the reason that exposes the magma inside. Lava is a semi-fluid (molten rock) rock that happens due to volcano eruption (fissure). 

You can also name the solidified molten rocks as lava. The molten lava flow may deposit at some cold and flat surface. This page can help you to know; how and why volcanoes erupt.

Speciality of Lava

You may find the temperatures of molten lava very high before they solidify. The temperature of molten lava varies from 1,300 to 2,200°F (700 to 1,200°C). 

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The material behaves like a hot liquefied substance. It can flow like hot and molten syrup. Sometimes, it becomes incredibly stiff so that you won’t notice any further flowing. The viscosity of the lave will be higher when the silica content inside the lava is higher. 

Mafic is also one type of lava. This lava is like ferromagnesian and dark-coloured like basalt. The Hawaiians have given a name to mafic called ‘pahoehoe’ and aa (or a’a). 

Pahoehoe’s lava can relax when it finds a smooth surface with mildly undulating or broadly hummocky soil. The liquid lava contains a thin and still-plastic crust that drags beneath it. 

After some interval (a few days at least), it converts into rolls and folds like a tapestry. It will totally look like a bunch of twisted ropes lying around the soil. 

In Hawaii, the lava called Pahoehoe flows are faded somehow. However, you can notice that liquid lava streams are getting the passage beneath a stronger (solidified molten lava) or short-term frozen surface. 

Basaltic lava is also known as pahoehoe and has the margin of a flow. It is responsible for the sticking out of molten lava over one small toe or lobe after another.

Magma

Magma is a term that was used in ancient greek. This means thick unguent. Magma behaves like a molten rock that has some amount of volatile substances. All of these substances are present inside the core of the earth. Geologists may find these magma-contains lie below the earth’s surface. 

Magma has a certain amount of chambers called magma chambers. 

Inside each chamber, you can find an assemblage of suspended crystals, dissolved gases, and gas bubbles. The heat that endures within magma has a higher range of temperature. The temperature of magma lies between 1300 and 2400 degrees.

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It behaves as a molten or semi-molten state of all igneous rocks that combine together in a hot-liquefied form. Also, magma has other stuff besides molten rock, such as gas bubbles and suspended crystals.

Physical and Chemical Structure of Magma

The property of many magmatic liquids is they possess a higher amount of silica. The volcano has silicate melts in higher amounts. Each silicate compound is composed of certain earth-core materials such as: 

• Silicon

• Oxygen 

• Aluminium 

• Iron 

• Magnesium

• Calcium

• Sodium

• Potassium

A volcano has a physical behaviour that it melts during its eruption. So, certain factors are thereupon which it depends upon. Such factors are:

1. Atomic Structures of Comprised Materials 

2. Temperature 

3. Pressure

4. Material Composition

The viscosity of lava is also a fact and an identical property that stands superior for understanding magmas’ behaviour. As we know, magma’s viscosity depends on temperature; however, composition plays a higher role in understanding the magma than the temperature. 

The silicon ion is an exciting kind of ion. It is small and highly charged within the active lava. Silicon ions have a higher capacity to merge with four oxygen ions to form a tetrahedral arrangement. 

This arrangement forms around together to develop another smaller silicon ion. The name of the ion is ‘silica tetrahedron’. 

Different types of magma are also there, which have a few amounts of silicon that exist within it. It contains an isolated form of silica tetrahedra. When the level of silicon rises, then the process of polymerization of silica tetrahedra begins partially.  

This process tends to form different chains, sheets, and clumps of silica tetrahedra. All of them are joined by the bridging of oxygen ions. This is the process that helps increase the viscosity of the magma.

Reason Behind the Eruption of Volcanoes 

The mantle of Earth is divided into certain portions. It has a certain amount of crust that is classified into different sections. All these classifications are based on individual seismology. 

The conditions that help to promote the eruption of volcanoes are the continuous rise of temperature and pressure. These two factors can change the crust dramatically out of the mantle location. This process leads to continuous volcanic eruption as the temperature in that region should have crossed beyond 1000 o C.