volcanic eruptions that go on for weeks n weeks with slow moving lava,?

This 'leaking' is quite common. In fact if it has been going on for a very long time these vents, as they are known, actually reduce the chance of a very large explosion because they release pressure. It is when lots of them pop up all at the same time that you should start to worry :)

The magma is called aa, it is the more viscous kind.

Hi libragirl,

It sounds like the type of volcano you are talking about here, is a Sheild Volcano. They are large, broad, dome-shaped volcanos typical of the Hawaiian Island & Iceland. They ttypically emit a slow-moving basaltic lava called "Aa" lava. In fact, sometimes the lava flow from a Sheild volcano is so slow, that a person could outwalk it (though some Sheild eruptions can be more sudden & catastrophic).

Most Sheild volcanos have grown up from the deep ocean floor, from intraplate igneous activity (as opposed to plate boundaries). This intraplate volcanism is caused by Hotspots & occurs when a mantle plume rises up toward the surface. Sheild Volcanos are the largest volcanoes on Earth.

to expound upon jeeba....

This type of volcano is usually called a "shield" volcano due to its shape. This type of volcano rarely has explosive eruptions, the rock type coming out is rich in iron, and originates from seafloor material.

The volcanoes that cause lots of destruction and death are cinder cones, their originating material is continental rock, richer in feldspars. They tend to clog, build huge amounts of pressure over time, and once in awhile (like a few hundred years) explode violently with a lot of ash. This is like Vesuvius or Mt. St. Helens.

The type of volcano you're describing is more like the Hawaiian type. They'll erupt gently every few years with a very liquid lava, and they'll turn on and off much more frequently releasing pressure. The composition and viscosity of the flows vary somewhat from one volcano to another, so each volcano has its own particular characteristics as what it does when it's becoming active or becoming inactive. Shield volcanoes, however, are usually pretty safe to live near because since their lava is very liquid, they don't get those explosive flows.

Some volcanoes, like ones in the Phillipines, will once in a few hundred years have an explosive eruption with a lot of ash, and then switch over to a more gently flowing liquid lava as they finish up.