Question

The topographic map is a USGS produced image of Mt. St. Helens before and after its 1980 eruption. The slope of the northern flank of the volcano was __ before the eruption and __after.

Answer 1

The northern slope of Mount St. Helens was increasingly unstable before the 1980 eruption and became smooth after, due to the deposition of volcanic ash and other materials from the eruption. This drastic transformation led to a process of primary succession in the affected area.

Step-by-step explanation:

The slope of the northern flank of Mount St. Helens was increasingly unstable before the eruption and smooth after. Before the eruption, geological studies indicated a growing instability in the north flank, leading to closure of the surrounding area due to landslide and avalanche threats. The devastating 1980 eruption led to a massive landslide and the collapse of the mountain's northern slope, greatly altering the landscape. The resultant deposition of volcanic ash and other materials created a new soil, which formed a smooth landscape that is slowly being eroded by rainfall forming small rivers and valleys.

Since the eruption, the affected area north of Mount St. Helens is undergoing a natural recovery process although free of the original ecosystem's remnants, including seeds that were stored in the soil. This significant change in the ecosystem would lead to a process known as primary succession, where a new community of organisms slowly colonizes the newly formed volcanic debris soil.