3.5 - Impacts of Tectonic Hazards - notes
3.5 - Impacts of Tectonic Hazards
Primary impacts of earthquakes
Tectonic hazards, such as earthquakes, have immediate and direct consequences known as primary impacts. These effects occur as a result of the intense ground shaking during the event.
Direct consequences of earthquake ground shaking
- Structural collapse - Buildings and infrastructure can be severely damaged or completely destroyed due to the violent shaking of the ground.
- Human casualties - People may be injured or killed by falling debris or collapsing structures.
- Utility damage - Essential services like water, gas, and sewage pipelines can rupture, leading to immediate disruptions.
- Power outages - Electric power lines are often brought down, resulting in widespread loss of electricity in affected areas.
Secondary impacts of earthquakes
Beyond the initial destruction, earthquakes often lead to secondary impacts. These are indirect effects that occur after the main event, often as a result of the primary damage.
Indirect consequences following earthquakes
- Tsunamis - Coastal areas may experience massive waves triggered by underwater seismic activity, causing further destruction.
- Aftershocks - Smaller tremors following the main earthquake can cause additional damage to already weakened structures.
- Fires - Ruptured gas mains can ignite fires, which may spread rapidly and cause further devastation.
Primary impacts of volcanic eruptions
Volcanic eruptions also produce immediate, direct effects known as primary impacts. These result from the eruption itself and the materials it releases.
Direct consequences of volcanic activity
- Destruction by lava flows - Lava can engulf and destroy buildings, roads, and agricultural land in its path.
- Human casualties - People may suffer injuries or fatalities due to direct exposure to lava, ash, or gases released during the eruption.
- Water contamination - Falling ash can pollute water supplies, making them unsafe.
Secondary impacts of volcanic eruptions
Following the initial eruption, secondary impacts emerge as indirect consequences.
Indirect consequences following volcanic eruptions
- Lahars - These destructive mudflows form when volcanic ash and debris mix with rainwater or melted snow, flowing down slopes.
- Fires - Lava and hot pyroclastic flows can ignite fires, which may spread.
- Psychological trauma - The loss of loved ones, homes, and livelihoods can lead to significant emotional distress, a common secondary impact of all tectonic hazards.
TermDefinition
Primary impactAn immediate consequence that occurs directly as a result of the hazard itself, such as ground shaking or a lava flow.
Secondary impactAn indirect consequence that happens after the main event, often triggered by the primary damage.
TsunamiA large ocean wave generated by underwater earthquakes or volcanic eruptions displacing massive volumes of water.
AftershockA smaller earthquake that follows the main shock, often causing further damage to weakened structures.
LaharA destructive mudflow formed when volcanic ash and debris mix with water from rain or melted snow.
Key points to remember
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