Spatter cone in the context of Cone (geometry)

A fissure vent, also known as a volcanic fissure, eruption fissure or simply a fissure, is a linear volcanic vent through which lava erupts, usually without any explosive activity. The vent is often a few metres wide and may be many kilometres long. Fissure vents can cause large flood basalts which run first in lava channels and later in lava tubes. After some time, the eruption tends to become focused at one or more spatter cones. Volcanic cones and their craters that are aligned along a fissure form a crater row. Small fissure vents may not be easily discernible from the air, but the crater rows (see Laki) or the canyons (see Eldgjá) built up by some of them are.

The dikes that feed fissures reach the surface from depths of a few kilometers and connect them to deeper magma reservoirs, often under volcanic centers. Fissures are usually found in or along rifts and rift zones, such as Iceland and the East African Rift. Fissure vents are often part of the structure of shield volcanoes.

Zuqar Island (Arabic: جزيرة زقر, romanized: jazīra zuqar) is an island in the Red Sea that belongs to Yemen. It lies between the coasts of mainland Yemen and Eritrea, near the Bab-el-Mandeb strait which connects the Red Sea to the Gulf of Aden. Despite its proximity to the African continent, Zuqar Island is considered a part of Asia because it sits on the Asian continental shelf. It is approximately 130 square kilometres (50 sq mi).

The island consists of a shield volcano overlain by basaltic pyroclastic cones and spatter cones which produced youthful-looking pahoehoe lava flows. Several small coastal cones and islets surrounding Zuqar Island were formed by phreatic eruptions.