Where Earthquakes Occur

Location of Earthquakes

Earthquake's occur at convergent, divergent and transform plate boundaries.
The most dangerous earthquakes are associated with subduction zones.
The subduction zone off the coast of Japan is the most deadly in the world as the Pacific plate is brought under the Eurasian plate.
This area is part of the Pacific Ring of Fire – where the world's most active volcanoes and earthquakes are.
Earthquakes can also occur at transform plate boundaries such as the San Andreas fault.
They also occur at divergent plate boundaries such as the Mid Atlantic Ridge but they are not frequent or dangerous.

7.8 magnitude earthquake hit 77km north of Nepal's capital city, Kathmandu
This region lies along an active fault line over 1,000km long and this earthquake was a dangerous shallow earthquake as the focus was only approx. 15km below the surface of the Earth
It directly/indirectly affected 8 million people
Indian plate and overriding Eurasian plate collided – they are converging at a rate of 5cm per year and this collision is why the Himalayan mountain range is getting higher (Mt. Everest is still growing)
Original earthquake was followed by strong aftershocks and another earthquake triggered by the stress of this seismic activity
The last major earthquake to hit the region was in 1934 when 17,000 people were killed. The pattern of earthquakes in this region have been recorded since the 13th century with seismic gaps of 75-80 years
The biggest aftershock came on the 12th of May – 17 days after the original earthquake hit and it registered 7.3 on the Richter Scale. The epicentre was 76km away from the Mt. Everest base camp. It affected Northern India, Tibet and Bangladesh, killing 48 people and injuring up to 1,000 people. 6 more aftershocks were also felt in the region with none of these recording a strength of more than 5 on the Richter Scale.

8,000 killed, 10,000 injured
Rescue teams used sniffer dogs and heat-seeking equipment to search for survivors for the days after but this was not possible in remote areas, so local people had to search through the rubble
Many villages were destroyed or buried by avalanches and landslides (earthquakes and aftershocks caused 3,000 of these) such as those in Langtang Valley 435 people lived here but now only one house still exists as the rest slid 700 metres downhill
130,000 buildings destroyed, including 60m high Dharahara Tower built in 1832 for queen of Nepal
24,000 were homeless having fled the region
Immediate cremation of deceased was ordered to prevent the spread of disease
Tourism was majorly affected and is a big long-term effect, causing economic downturn
- Over 100,000 visitors trekked Mount Everest and the surrounding region in 2013, providing a major source of income for locals
- Due to safety fears these numbers have massively declined
Difficult terrain meant that delivering aid (food, shelter, clean water) was slow
Nepal govt. estimated that they needed €1.7 billion in aid to rebuild and repair infrastructure such as roads and hospitals
- Govt. has been criticised for being corrupt in the past so this aid is slow in coming with UN giving €3 million in aid and Ireland delivering 63 tonnes of life-saving supplies
- But future growth and redevelopment will be very difficult and slow

28 countries in the Pacific have tsunami warning systems including Japan
Tsunami sensors collect data on the ocean floor as do tide gauges
This information is then transmitted via a satellite to tsunami warning centres to be interpreted
Regular updates are then provided on local television and radio stations
Local authorities are responsible for evacuation plans

8.9 magnitude Earthquake lasting 2 and a half minutes, 130km off the coast of Japan also causing a Tsunami
Japan is located on a convergent plate boundary at a subduction zone, marked by the deep-sea Japan trench – part of the Pacific Ring of Fire
- Here, the Pacific Plate is sinking underneath the Eurasian Plate
Tension built up between the two plates and eventually the edge of the Eurasian Plate jumped backwards 5-8 metres over a 180km stretch of land
A shallow focus earthquake occurred as a result which displaced a large volume of water, creating a tsunami
The waves remained quite small in the ocean but built up to approx. 10 metres high once they hit the shallow water
The huge wave flew inland for several kilometres leaving a path of destruction in its wake
Tsunami warnings were only received 10 minutes before the wave hit so locals did not have time to react

Coast was transformed into a muddy swamp of material thrown up by the tsunami
Towns and villages were completely destroyed including a town of 10,000 people
27,000 people were killed with 90% of them drowning as a result of the tsunami
Fukushima nuclear power plant was damaged sparking fears of a radioactive leak – a state of emergency was declared as a result with a 20km radius cleared around the plant as radioactive material leaked out
500,000 left homeless but the earthquake itself did little structural damage due to Japans strict building regulation