What Are The After Effects Of A Volcano?

I think you are referring to a volcanic eruption. There is a possibility of a lot of rain, thunder and lighting following an eruption. There are huge explosive eruptions that fling material into the stratosphere. If it reaches the troposphere, it gets washed away in the form of rain. There can also be possible after-effects in the form of storm or strong wind. There are people who attribute the phenomena of 'El Nino' to volcanic eruptions.  

The after effects of a volcano can be in many forms. It can result in the creation of new islands and land forms. It can lead to deposition of minerals. It can lead to creation of beautiful locales. It can even be an impetus to the tourism industry.  However it can obliterate old crops and old fauna. It is known to have destroyed towns and cities. It has even been known to have generated devastating phenomena known as Tsunami.