This included all hospitals in the capital; air, sea, and land transport facilities; and communication systems.

Notable landmark buildings were significantly damaged or destroyed, including the Presidential Palace, the National Assembly building, the Port-au-Prince Cathedral, and the main jail.

Among those killed were Archbishop of Port-au-Prince Joseph Serge Miot, Many countries responded to appeals for humanitarian aid, pledging funds and dispatching rescue and medical teams, engineers and support personnel.

Shaking damage was more severe than for other quakes of similar magnitude due to the shallow depth of the quake.

The quake occurred in the vicinity of the northern boundary where the Caribbean tectonic plate shifts eastwards by about 20 mm (0.79 in) per year in relation to the North American plate.

Witnesses told reporters that the sea first retreated and a "very big wave" followed rapidly, crashing ashore and sweeping boats and debris into the ocean.

Amongst the widespread devastation and damage throughout Port-au-Prince and elsewhere, vital infrastructure necessary to respond to the disaster was severely damaged or destroyed.

Nearly two weeks later it was reported that the beach of the small fishing town of Petit Paradis was hit by a localised tsunami shortly after the earthquake, probably as a result of an underwater slide, and this was later confirmed by researchers.

At least three people were swept out to sea by the wave and were reported dead.

Communication systems, air, land, and sea transport facilities, hospitals, and electrical networks had been damaged by the earthquake, which hampered rescue and aid efforts; confusion over who was in charge, air traffic congestion, and problems with prioritising flights further complicated early relief work.

Port-au-Prince's morgues were overwhelmed with tens of thousands of bodies. As rescues tailed off, supplies, medical care and sanitation became priorities.

Delays in aid distribution led to angry appeals from aid workers and survivors, and looting and sporadic violence were observed.