Whose abolitionist novel, published in 1852, “started this big war”?

Harriet Stowe, is the right answer.

Explanation:

An abolitionist and author from America who gave a direct opposition to the government is Harriet Elisabeth Beecher Stowe. She wrote a novel named "Uncle Tom's Cabin; or, Life Among the Lowly" to protest against the Fugitive Slave Act. This novel installed a platform for the American Civil War.

b toward the volcano.landward. the landward side of something is the side nearest to the land or facing the land, rather than the sea.