Simpler Version:
In 1942, a Mexican farmer named Dionisio Pulido heard a loud noise coming from his cornfield. It wasn’t thunder, but a crack in the ground that was smoking and releasing gas and rocks. This crack became known as the Paricutin volcano, and for the next 9 years, it covered a large area with lava and ash. But where did this volcano come from, and what caused it to erupt?
Volcanoes start with magma, which is molten rock. Magma forms when ocean water enters the Earth’s mantle and lowers the melting point of the rocks there. Normally, magma stays underground because of the weight of the Earth’s crust pushing down on it. But sometimes, the pressure from the magma becomes too strong, and it can cause an eruption. This happened with the Paricutin volcano in Mexico.
One reason for an eruption is when the magma contains gases that can’t dissolve anymore and form bubbles. When these bubbles reach the surface, they explode and release ash into the air. Another cause is when the rock above the magma chamber becomes too weak and can’t hold the magma back anymore. This can happen due to landslides or tectonic activity.
Unfortunately, predicting eruptions is difficult because it’s hard to measure changes in magma pressure. However, scientists are using new technology like thermal imaging and spectrometers to study volcanoes and understand their eruptions better.
Same Version:
In February of 1942, Mexican farmer Dionisio Pulido heard what he thought was thunder coming from his cornfield. However, it wasn’t coming from the sky. The source of the sound was a large crack in the ground that was emitting gas and ejecting rocks. This crack would later be known as the Paricutin volcano, and over the next 9 years, it would cover an area of over 200 square km with lava and ash. But where did this new volcano come from, and what triggered its unpredictable eruption?
The story of any volcano begins with magma, which is molten rock. Magma usually forms in areas where ocean water enters the Earth’s mantle and lowers the melting point of the rocks there. The resulting magma remains underground due to the delicate balance of three geological factors. The first factor is lithostatic pressure, which is the weight of the Earth’s crust pushing down on the magma. The second factor is magmastatic pressure, which is the pressure exerted by the magma pushing back. The third factor is the rock strength of the Earth’s crust, which strains under the battle between the lithostatic and magmastatic pressures. Normally, the rock is strong enough to keep the magma in place. However, when this equilibrium is disrupted, it can lead to explosive consequences.
One common cause of volcanic eruptions is an increase in magmastatic pressure. Magma contains various elements and compounds, some of which dissolve in the molten rock. At high concentrations, certain compounds like water or sulfur can no longer dissolve and instead form high-pressure gas bubbles. When these bubbles reach the surface, they can burst with great force, similar to a gunshot. If millions of bubbles explode simultaneously, they can send plumes of ash into the stratosphere. Before they burst, these bubbles act like carbon dioxide bubbles in a shaken soda, reducing the density of the magma and increasing the upward buoyant force through the crust. Many geologists believe that this process was responsible for the eruption of the Paricutin volcano in Mexico.
There are two known natural causes for the formation of these buoyant bubbles. Sometimes, new magma from deeper underground brings additional gassy compounds into the mix. Other times, bubbles can form when magma begins to cool and solidify. As the molten rock hardens, some minerals solidify into crystals, leaving behind a higher concentration of compounds that can form explosive bubbles.
Not all eruptions are caused by rising magmastatic pressure. Sometimes, the weight of the rock above a magma chamber can become dangerously low. Landslides can remove large amounts of rock from the top of the chamber, instantly triggering an eruption by reducing the lithostatic pressure. This process is known as “unloading” and has been responsible for various eruptions, including the sudden explosion of Mount St. Helens in 1980. Unloading can also occur over longer periods of time due to erosion or melting glaciers. In fact, some geologists are concerned that glacial melt caused by climate change could lead to increased volcanic activity.
Finally, eruptions can occur when the rock layer is no longer strong enough to contain the magma below. Acidic gases and heat escaping from the magma can gradually corrode the rock through a process called hydrothermal alteration, turning hard stone into soft clay. Tectonic activity can also weaken the rock layer. Earthquakes can create fissures that allow magma to escape to the surface, and the Earth’s crust can be stretched thin as continental plates shift away from each other.
Unfortunately, even with knowledge of the causes of eruptions, predicting them remains challenging. Measuring changes in magmastatic pressure is difficult due to the depth and heat of magma chambers. However, volcanologists are constantly developing new technology to better understand these explosive events. Advances in thermal imaging have enabled scientists to detect subterranean hotspots, spectrometers can analyze gases escaping from magma, and lasers can precisely track the impact of rising magma on a volcano’s shape. With these tools, it is hoped that a deeper understanding of volcanic vents and their eruptions can be achieved.
More Complex Version:
In the month of February in the year 1942, a Mexican farmer by the name of Dionisio Pulido was startled by a peculiar sound emanating from his cornfield. Initially mistaking it for the rumble of thunder, Pulido soon realized that the source of the noise was not the heavens above, but rather a large, smoking crack in the earth’s surface. This fissure, emitting gas and ejecting rocks, would later be christened as the Paricutin volcano, and over the course of the subsequent 9 years, its fiery lava and ash would blanket an expansive area spanning over 200 square kilometers. Yet, the genesis of this newfound volcano and the catalyst behind its capricious eruption remained enigmatic, begging the question: from whence did this volcanic phenomenon arise, and what triggered its unpredictable outburst?
The genesis of any volcano is intrinsically tied to the presence of magma, a molten rock that typically forms in regions where oceanic water infiltrates the Earth’s mantle, thereby lowering the melting point of the surrounding rocks. Under normal circumstances, this resulting magma remains ensconced beneath the Earth’s surface, owing to the delicate equilibrium maintained by three geological factors. The first of these factors is lithostatic pressure, which denotes the weight of the Earth’s crust exerting downward force upon the magma beneath. In response, the magma exerts magmastatic pressure, a counterforce that pushes back against the lithostatic pressure. The third factor at play is the rock strength of the Earth’s crust, which is strained by the interplay between the lithostatic and magmastatic pressures. Ordinarily, the rock possesses sufficient strength and heft to retain the magma in its subterranean abode. However, when this equilibrium is disrupted, the consequences can be explosively cataclysmic.
One of the most prevalent causes of volcanic eruptions is an escalation in magmastatic pressure. Magma comprises an amalgamation of diverse elements and compounds, many of which dissolve within the molten rock. At elevated concentrations, certain compounds such as water or sulfur reach a saturation point, precipitating the formation of high-pressure gas bubbles. When these bubbles ascend to the surface, they rupture with the force akin to that of a gunshot. In instances where millions of bubbles detonate simultaneously, the resultant energy can propel plumes of ash skyward, penetrating the stratosphere. Prior to their rupture, these bubbles function akin to carbon dioxide bubbles within an agitated soda, diminishing the density of the magma and augmenting the buoyant force propelling it upwards through the crust. Numerous geologists posit that this very process underpinned the eruption of the Paricutin volcano in Mexico.
The formation of buoyant bubbles within magma can be attributed to two known natural causes. On occasion, fresh magma originating from deeper subterranean realms introduces additional gaseous compounds into the mix. Alternatively, bubbles can arise when magma commences its cooling process. In its molten state, magma represents a fusion of dissolved gases and liquefied minerals. As the molten rock cools and solidifies, certain minerals crystallize, leaving behind a higher concentration of compounds that are prone to forming explosive bubbles.
It is important to note that not all volcanic eruptions are precipitated by the ascent of magmastatic pressure. In certain instances, the weight of the rock stratum above a magma chamber can diminish to perilously low levels. Landslides, for instance, possess the capacity to dislodge substantial quantities of rock from atop a magma chamber, thereby precipitating an instantaneous eruption by reducing the lithostatic pressure. This phenomenon, known as “unloading,” has been implicated in numerous eruptions, including the abrupt cataclysm that befell Mount St. Helens in 1980. Unloading can also occur over protracted periods of time, owing to processes such as erosion or the melting of glaciers. In fact, a growing concern among geologists is that the glacial melt induced by climate change could potentially engender heightened volcanic activity.
Finally, eruptions can transpire when the rock stratum can no longer withstand the pressure exerted by the magma beneath. The escape of acidic gases and heat from the magma can gradually corrode the surrounding rock through a process known as
