Blue Lake Crater is considered a Holocene maar (a broad, low-relief volcanic crater) with at least three overlapping explosion craters, which trend to the northeast. There is a crescent-shaped, agglutinate ridge consisting of volcanic bombs surrounding the crater, which reaches heights of above the lake surface and above surrounding topographic features. Some of the volcanic bombs on the outer slopes of Blue Lake Crater reach lengths of ; many of the inner slopes lead to cliffs. The northern wall of the crater appears to have collapsed during an eruption, while the southern wall is intact and made of cinder and a matrix of bedrock and volcanic bombs. Overall, Blue Lake Crater has a modest volcanic cone.