Distance from the epicentre - the effects of an earthquake are more severe at its centre.
The higher on the Richter scale, the more severe the earthquake is.
Level of development (MEDC or LEDC) - MEDCs are more likely to have the resources and technology for monitoring, prediction and response.
Population density (rural or urban area). The more densely populated an area, the more likely there are to be deaths and casualties.
Communication - accessibility for rescue teams.
Time of day influences whether people are in their homes, at work or travelling. A severe earthquake at rush hour in a densely populated urban area could have devastating effects.
The time of year and climate will influence survival rates and the rate at which disease can spread.