The document summarizes the effects of a major earthquake and tsunami that struck off the coast of Sumatra, Indonesia on December 26, 2004. It notes that a 9.0 magnitude earthquake triggered a tsunami that hit Sri Lanka 1.5 hours later. It also provides definitions of primary effects that result directly from a natural disaster, like buildings collapsing, versus secondary effects that are indirect consequences, such as homelessness, unemployment, or environmental impacts.