Backgrounder: Weeklong quakes rock Pacific rim, Haiti

BEIJING, Jan. 13 (Xinhua) -- Since Saturday last week, a series of earthquakes have kept rocking the Pacific rim and then crossed over the land strip separating the Pacific from the Atlantic to strike Haiti.

The series of earthquakes first rocked California of the United States on Saturday last week with a magnitude of 6.5 before a magnitude-4.9 tremor shook the border areas between Honduras and Guatemala.

On Tuesday, a quake measuring 5.6 on the Richter scale hit Indonesia before the magnitude-7.0 temblor hit Port au Prince of Haiti for the country's ever-recorded strongest earthquake.

Haiti was last hit by a strong quake measuring 6.7 in 1984.

Earthquakes are frequent along the Pacific rim, where 81 percent of the world's largest earthquakes occur to shake the land and cause tsunami.

But safely walled off by the land strip separating the Pacific from the Atlantic, Haiti has been safe from devastating earthquakes until Tuesday.

Office and residence buildings including the presidential palace, ministerial offices, a hospital and a cathedral were reported to have collapsed.

So far, there were no confirmed casualties in the Haiti earthquake.

For quick references of earthquakes in the region of the Pacific rim and the Caribbean:

The region's deadliest earthquake killed 140,000 people in Tokyo of Japan in 1923

The strongest earthquake recorded in the world (a magnitude-9.5) hit Chile on May 22, 1960.

The largest recorded earthquake in the United States (a magnitude-9.2) struck Alaska on March 28, 1964.

Japan was hit again by another lethal earthquake in January of 1995 when more than 6,430 people lost their lives to a magnitude-7.3 quake.

Geologically, where land masses meet, they form seismic faults that in turn cause earthquakes through friction, ramming into and pulling away from one another.