Geophysical hazards

Haiti Earthquake (2010)

A devastating earthquake with a magnitude of 7.0 that struck Haiti, causing severe destruction, approximately 300,000 deaths, and leaving over 1 million homeless.

Epicenter

The point on the Earth's surface directly above the focus of an earthquake; for the Haiti earthquake, it was located in the town of Leogane.

Speed of onset

The time it takes for a hazard to develop; the Haiti earthquake had no warning and occurred suddenly.

Context and vulnerability Haiti

Factors that increase susceptibility to disaster effects; in Haiti, these included poor housing conditions characterized by inadequate infrastructure and materials, high population density in urban areas which exacerbates the impact of disasters, widespread poverty limiting access to emergency resources, and an underdeveloped health system that struggles to respond to crises.

Aftershocks

Smaller earthquakes that occur in the same area after a larger earthquake; Haiti experienced 52 aftershocks following the main quake.

Environmental impact of the Haiti Earthquake

Included deforestation, pollution of water supplies, and significant damage leading to a cholera epidemic.

Christchurch Earthquake (2011)

A magnitude 6.3 earthquake that struck Christchurch, New Zealand, on February 22, 2011. It caused 185 fatalities, injured over 2,000 people, and resulted in extensive damage to infrastructure, with an estimated economic cost of NZD 40 billion. The earthquake also triggered widespread disruption, including significant damage to the central business district, schools, and homes, and led to a massive recovery effort.

Lahar

A type of volcanic mudflow, significant in the Mt. Helen eruption; lahars from the eruption reached the Cowlitz River.

Eruptions return interval

The average time between volcanic eruptions; Nyiragongo's eruptions occur roughly every 20 years.

Secondary hazards

Hazards that occur as a result of the primary event; for the Nyiragongo eruption, these included gas emissions and potential lake explosions.

Kalimpong Landslides

Landslides in Kalimpong, India, attributed to poor water management and slope instability, exacerbated during monsoon seasons.

Frequency of landslides

Typically occurs about 50 times a year in Sri Lanka, especially during the monsoon seasons.

Magnitude of the Sri Lanka Landslide (2016)

The landslide in 2016 resulted in 93 fatalities and damage to over 58,000 houses.

Volcanic Explosivity Index (VEI)

A scale that measures the explosiveness of eruptions; Nyiragongo's eruption had a VEI of 1, indicating a low explosive potential.

Poor water management

A significant factor causing landslides in Kalimpong, where uncontrolled discharge of water contributes to slope instability.