Earthquakes: Unseen Pollution Culprit And Its Devastating Impact

Earthquakes are a natural calamity that can have devastating consequences for human life and the environment. While property destruction and loss of life are often the most immediate concerns, earthquakes can also cause significant pollution, affecting the air, water, and soil. This introduction will explore the various ways in which earthquakes can lead to pollution and the potential impact on human health and the environment. From the release of toxic gases and the stirring up of dust to water pollution and industrial accidents, the environmental fallout of earthquakes is far-reaching and requires attention to mitigate their effects.

Earthquakes release dust and other pollutants into the air

Earthquakes can cause a lot of air pollution through the release of dust and other accumulated pollutants. The vibrations and tremors from earthquakes can cause buildings and homes to crumble, releasing dust and driving it into the air. Tectonic shifts can also disrupt sediment, exposing it to the air where it lingers as particulates.

In 2015, a powerful 7.8 magnitude earthquake hit Nepal, levelling many buildings constructed of old bricks. This resulted in a huge increase in dust particles, severely affecting the country's air quality. According to the EPI, Nepal ranked 176th in air quality among 180 countries in 2018, with pulmonary diseases comprising 43% of all hospital visits.

The jolt of an earthquake can also release dust that is normally packed away in homes, underscoring the importance of keeping a clean living space. Additionally, earthquakes can cause accidental fires and damage pipelines or storage facilities, leading to the release of chemicals and volatile organic compounds (VOCs) into the atmosphere.

Another consequence of earthquakes is the increased risk of water pipes and other structures being damaged, resulting in damp conditions that encourage the growth of mould and other microbial organisms. These organisms release spores that are known air pollutants and can have acute effects on respiratory systems.

Furthermore, earthquakes may release methane from pockets within the earth, typically located at sub-sea levels. Methane is a greenhouse gas that is much more harmful than carbon dioxide when released uncombusted into the atmosphere. It traps heat from the sun and contributes to the Earth's increasing surface temperatures.

They can cause the release of methane from pockets within the earth

Earthquakes can cause the release of methane from pockets within the earth. This happens when the shifting of tectonic plates results in the fracturing of sediments, allowing methane to escape from its underground reservoirs.

Methane is a highly potent greenhouse gas that is much more harmful than carbon dioxide when released uncombusted into the atmosphere. It has a shorter lifespan, remaining in the atmosphere for only about a decade. However, it is significantly more damaging than carbon dioxide over a 100-year period, with a warming potential 25 times greater. This is because methane is very effective at trapping heat from the sun, contributing to the Earth's increasing surface temperatures and exacerbating the effects of climate change.

In 2007, researchers from the University of Bremen in Germany and the Alfred Wegener Institute in Bremerhaven, along with colleagues from the ETH in Zurich, discovered evidence of methane release in the Arabian Sea. They analysed sediment cores from the seabed and found that one core, located just 1.6 metres (5.2 feet) below the seafloor, contained methane hydrates—a solid, ice-like mixture of methane and water. Additionally, they found chemical signatures indicating that large quantities of methane had flowed through the sediments at some point in the past.

By examining seismic records, the researchers identified a magnitude 8.1 earthquake that occurred in the same area in 1945. This earthquake, centred less than 15 miles from where the sediment cores were taken, is believed to have caused the release of methane. The seismic waves would have propagated through the seabed at extremely high speeds, fracturing the sediments and disrupting the gas hydrates that normally act as a barrier to contain methane.

The researchers estimate that approximately 7.4 million cubic metres of methane, equivalent to the capacity of about 10 large gas tankers, have been released from that single location since the 1945 earthquake. This calculation is conservative, as it does not include the amount of methane that escaped during the earthquake itself, and there may be other sites in the area that were also affected by the seismic event.

Earthquakes can result in water pollution due to an influx of sediments

Earthquakes can have a detrimental impact on the environment, causing pollution in the air, soil, and water. Water pollution, specifically, can occur due to an influx of sediments triggered by an earthquake. This is how it happens:

Sediment pollution occurs when excessive particles of soil, sand, and silt are washed into bodies of water, degrading water quality and endangering aquatic life. Earthquakes, with their powerful vibrations and tremors, can dislodge large amounts of sediment, sending them towards nearby water sources. The tremors can cause the soil to become loose and unstable, making it more susceptible to erosion and increasing the risk of sediment runoff.

The impact of sediment pollution on aquatic ecosystems is significant. The influx of sediments can lead to increased turbidity, reducing light penetration and inhibiting the photosynthetic activity of aquatic plants. This, in turn, affects the entire food chain within the ecosystem. Additionally, the sediments can smother fish and block the sunlight needed by aquatic plants, further disrupting the natural balance.

Moreover, sediment can act as a carrier for other forms of pollution, such as pesticides and heavy metals. As the earthquake-dislodged sediments make their way into water bodies, they can pick up and transport these additional pollutants, compounding the issue of water contamination. The consequences of such pollution can be dire, including the destruction of habitats and a decline in biodiversity.

The effects of sediment pollution extend beyond the ecological realm and have economic implications as well. For instance, increased sedimentation in rivers can disrupt navigation and lead to reduced channel depth. This can hinder river transportation and affect industries such as fishing and tourism, resulting in economic losses for communities dependent on these sectors.

To mitigate the impact of earthquake-induced water pollution, it is crucial to implement preventive measures. This includes strategies such as vegetation restoration, soil conservation practices, and the use of erosion control structures. By addressing the root causes of sediment pollution and improving land management practices, we can minimize the risk of water pollution and protect aquatic ecosystems and human communities that depend on them.

They can cause accidental fires and damage to industrial facilities, leading to the release of hazardous chemicals

Earthquakes can cause a lot of pollution, including air, soil, and water pollution. One of the main ways they can cause pollution is by triggering accidental fires and damaging industrial facilities, which can lead to the release of hazardous chemicals.

Accidental Fires

Fires are a common occurrence after earthquakes due to broken or damaged gas and electrical lines. As these lines break, fires can ignite and become challenging to control, especially with widespread structural damage and rescue operations already taxing emergency services. The resulting fires release various pollutants into the air, including carbon dioxide and other gases, further deteriorating the air quality index.

Damage to Industrial Facilities

Industrial equipment and systems are susceptible to structural damage during earthquakes. This damage can lead to accidental fires, explosions, and the dispersion of toxic substances. Atmospheric storage tanks, horizontal pressurized tanks, reactors, and pumps installed in industrial facilities can be severely affected, leading to the release of hazardous chemicals.

The release of hazardous chemicals from damaged pipelines or storage facilities can cause chemicals to leak and evaporate into the air, releasing large amounts of volatile organic compounds (VOCs) into the atmosphere. These fumes can easily penetrate human dwellings, especially in densely packed urban areas, posing significant risks to respiratory health.

The combination of accidental fires and damage to industrial facilities during earthquakes can have severe environmental and health consequences, emphasizing the importance of preparedness, safety measures, and effective risk mitigation strategies to minimize pollution and protect both human lives and the environment.

Earthquakes increase the risk of mould and microbial organisms due to damp conditions

Earthquakes can cause pollution in a variety of ways, including the release of dust, accidental fires and damage, and the creation of damp conditions that promote mould growth. This response will focus on the latter: earthquakes increase the risk of mould and microbial organisms due to damp conditions.

During an earthquake, water pipes and other similar structures are often damaged, resulting in more damp locations and spaces. These damp conditions are caused by water seeping into wooden structures, creating an environment that encourages fungal growth. The mould spores released are known air pollutants that can have acute effects on respiratory systems.

A case study conducted in New Zealand following the 2010 Canterbury earthquake and its aftershocks found that the PM10 particulate matter levels reached 140µg/m3 over a 24-hour period, far exceeding the NESAQ threshold of 50 µg/m3. The increased moisture and dampness in the environment due to water damage from the earthquake contributed to this spike in particulate matter levels.

To minimise the risk of mould growth and air pollution after an earthquake, it is recommended to keep ventilation closed as much as possible and maintain a clean home to reduce dust levels. While safety is the main priority during and after an earthquake, taking these additional precautions can help improve indoor air quality and reduce potential health risks.

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