SuperMoon Alert!

The biggest full moon of 2012 happens this weekend

You just might want to set your alarm or stay up for this one. The moon will be 14% bigger and 30% brighter than any other full moon in 2012.

The scientific term for it is 'Perigee Moon', which is explained in this video, along with other interesting facts about it. The big 2012 SuperMoon will be at its grandest at 11:34 PM (EDT) on Saturday night, May 5. (3:27)

From Wikipedia:

A "supermoon" is the coincidence of a full moon (or a new moon) with the closest approach the Moon makes to the Earth on its elliptical orbit, or perigee, leading to the technical name for a supermoon of the perigee-syzygy of the Earth-Moon-Sun system. The association of the Moon with both oceanic and crustal tides has led to claims that the supermoon phenomenon may be associated with increased risk of events such as earthquakes and volcanic eruptions. However, the evidence of such a link is widely held to be unconvincing.

The term supermoon is not widely accepted or used within the astronomy or scientific community, who prefer the term perigee-syzygy. Perigee is the point at which the Moon is closest in its orbit to the Earth, and syzygy is a full or new moon, when the Earth, the Moon and the Sun are aligned. Hence, a supermoon can be regarded as a combination of the two, although they do not perfectly coincide each time. Syzygy may occur within a maximum of 12 hours from perigee during a supermoon, and 1 hour from perigee during an extreme supermoon.

Effect on tides
 
The combined effect of the Sun and Moon on the Earth's oceans, the tide, is greatest when the Moon is either new or full. At lunar perigee the tidal force is even stronger, resulting in larger high and low tides on average, but even at its most powerful this force is still weak.
 
As the tidal force follows an inverse-cube law, that force is 18% greater than average. However, because the actual amplitude of tides varies around the world, this may not translate into a direct effect.
 
It has been argued that the supermoon of 19 March 2011 was responsible for the grounding of five ships in the Solent in the UK, however such claims are not supported by scientific evidence.
 
Speculative link to natural disasters
 
Richard Nolle has argued that within ±3 days of a supermoon, the Earth is more subject to natural disasters such as earthquakes and volcanic activity due to the Moon's increased gravitational force. Speculations have moved the goalposts to within 1 or 2 weeks of a supermoon to suggest a causal relationship with specific natural disasters such as the 2011 Tōhoku earthquake and tsunami and the 2004 Indian Ocean earthquake and tsunami. Such a widening of the effect window is unjustified as in both cases the Moon was farther from the Earth than average, making a supermoon effect impossible.
 
Some studies have reported a weak correlation between lunar activity and shallow, very low intensity earthquakes. However, no evidence has been found of any correlation with major earthquakes. Unjustified claims that the lunar tides trigger earthquakes are rooted in a lack of appreciation that the stress in the Earth is described by a tensor with six independent parameters and that earthquakes occur as slip on existing, weak fault planes. Any change in stress, by lunar tides, by impounding a reservoir, or by a large nearby earthquake, changes the local stress tensor in specific directions. If one wishes to estimate whether a given change advances or hinders slip on a fault, one has to know the orientation of the fault. It is equally likely that the change of the stress due to the moon clamps the fault shut, rather than advancing slip on it. This is why Ohtake has carefully considered the orientation of the fault planes in earthquakes that he showed were correlated with lunar tides.
 
The 2011 Tōhoku earthquake and tsunami is the only earthquake of 8.0 magnitude or greater to have occurred within 2 weeks of the 14 extreme supermoons from 1900 to the present date, suggesting that the claim of a supermoon effect on the incidence of large-scale earthquakes is unjustified.