Earthquakes

• Soil liquefaction occurs when shaking of the ground separates moisture from the geology and causes it to sit on top. This causes sinking of buildings. I can only happen to more saturated soils like clay.
• Primary P waves travel fastest and are caused by compression. Secondary S waves have a higher amplitude and cause the most damage as they move side to side.
• The Benioff zone is the subduction zone where plates cause friction and lead to partial melting. Subduction must take place for earthquakes to occur.
• Nepal had a 7.8 magnitude earthquake in 2015, which caused a landslide at the base camp of mount Everest which killed 19 people
• The seismic gap theory is the concept that if an area hasn't had a earthquake in a long period of time it's due for one, because of pressure needing to be released.
• Inter-crustal earthquakes occur between plates and causes by friction and pressure build up. They occur due to a sudden release of pressure.
• Intra-crustal earthquakes are internal stresses and can be due to human impacts, like weaponry testing.
• Early warning systems like shake alert give people enough time to prepare, like water and gas companies shutting valves to decrease resource loss and damage.
• Shake alert can also warn emergency responders and medical personnel. During the 2011 Japan earthquake the Bullet train was automatically slowed.
• Shake alert has limitations including it being useless if it is at the epicentre as well as missed phone notifications at night.