Earthquakes

Question 1

Nepal: facts

• Date
• Magnitude (Richter+Mercalli)
• Nepal - EQ-prone country rank

Answer 1

25th April 2015
M7.8 (Richter), IX (Mercalli)
11th most EQ-prone country in the world

Question 2

Nepal: human drivers of vulnerability

• Mean years of schooling
• Population density
• Urbanisation
• Building quality
• Warning systems/GDP

Answer 2

4.9 years of schooling
Gorkha district pop. density is 75 people/km^2
Urbanisation rate of 3% (fast)
80% of buildings are poorly engineered stone/brick houses, even in urban areas
No warning/monitoring systems. Has a GDP of $19.2bn

Question 3

Nepal: natural causes

• Type of plate boundary/plates involved
• Depth of focus
• 2 major fault systems in Himalayas

Answer 3

Convergent plate boundary - Indian plate subducted under the Eurasian plate
15km deep focus
Main Boundary Thrust and Main Central Thrust

Question 4

Nepal: hazardous nature

• Time length of EQ
• Number of aftershocks and their magnitude range
• Soil liquefaction detail

Answer 4

Lasted 50 seconds
300 aftershocks ranging from M4.0-6.7
Sand, silt and clay layers wit shallow ground water table caused soil liquefaction in the form of sand blows, and lateral spreading was observed in 12 locations

Question 5

Nepal: primary impacts

• Deaths/injuries
• Schools flattened
• Homes destroyed/damaged

Answer 5

9,000 deaths, 23,000+ injuries
7,000 schools flattened
600,000 homes destroyed, 288,000 damaged

Question 6

Nepal: secondary impacts

• Flooding => evacuation
• Avalanches
• Landslides
• Livestock losses
• Increase of people in poverty

Answer 6

The threat of flash flooding lead to the evacuation of thousands of people
EQ moved Everest by 3cm and caused avalanches that killed 22 climbers near base camp, the deadliest day
10s of landslides destroying villages and infrastructure occurred
17,000 cattle and 40,000 chickens lost
25% of electricity capacity lost

Question 7

Nepal: tertiary impacts

• Loss in tourism
• % of people still displaced

Answer 7

90% of tourist bookings cancelled, causing $600 million to be lost between 2015-2017
70% of people still displaced, becoming more susceptible to monsoon flooding and cold winters

Question 8

Nepal: management before

• Local preparation
• Seismic monitoring?

Answer 8

World Vision (humanitarian aid organisation) 2 at-risk districts organised the preparation of 65,000 people to reduce their risk. Community buildings fitted with EQ-resistant construction
No seismic monitoring techniques, meaning Nepal lacked the crucial 1 minute warning

Question 9

Nepal: management immediately after

• How many open spaces used for shelters
• Government spent an immediate ___ for relief
• How many needed food assistance
• Why was organised relief hard

Answer 9

16 open spaces used for temporary shelter as tremors made people fearful of being inside
$4.2 million in immediate relief
1.4 million people required food assistance, with nearly half of these in rural areas near the epicentre
Organised relief was hard due to landslides and bad weather, causing access and visibility from satellites to be worsened