Already with estimates of 200,000 dead and 1.5 million left homeless (European Union estimates), Haiti was struck with a second earthquake at 6:03 am local time. This earthquake, considered an aftershock of the 7.0 Magnitude quake that occurred last week, tipped the Richter scales at 6.1 Magnitude. The epicenter of this earthquake was located approximately 35 miles southwest of Port-au-Prince and its focus was 6.2 miles below the surface. So far, the 6.1 Magnitude earthquake is the largest of over 40 aftershocks which have occurred since the initial January 12th earthquake.
Aftershocks are a normal occurrence following earthquakes, caused by changes in the stress regime due to the initial movement (felt as an earthquake) along a fault plane. The total duration of these aftershocks varies greatly from hours to months or even years following a larger earthquake in the same location. However, the strength of aftershocks decreases over time. This is good news in the case of Haiti, since further aftershocks should be less significant.
I strongly recommend anyone interested in the how and why of earthquakes to visit the United States Geological Survey website and check out their FAQ section on earthquakes. There is a plethora of great information there which the news may not always accurately describe.
As with the last post, I would like to remind everyone that the Haitian people (over 3 million of them) continue to be in great need. There is little food or consumable water sources and shelter is obviously lacking. Please help by donating to the Red Cross or another reputable organization which will provide much-needed supplies and medical aid as survivors in need are still being pulled from the wreckage.