A couple of interesting connections, maybe just coincidences:

1. The eruption of Mount Tambora occurred very near to the beginning of the American Protestant religious revival known as the "2nd Great Awakening." The "year without a Summer" may have added a lot of fuel to that fire as people's crops failed and they sought a spiritual reason for the failure. There were many new religious sects formed as a result.

Because of crop-failure, the family of Joseph Smith was forced to move from Vermont to New York. It was in New York that Joseph found the tablets which led to the foundation of the Mormon church.

So, volcano ---------> Mormons, maybe.

2. Meanwhile in Europe, 1816 was the year that Mary Shelley and her friends vacationed at Lake Geneva. The volcanic eruption in 1815 made the weather cloudy, cold and rainy the entire time, so the group was forced to entertain themselves indoors by telling stories, which, famously, led to the creation of Frankenstein.

So if we hadn't had a volcano, we might not have Frankenstein.