Paka

Geography & Climate

Paka is located in Kenya, within the Kenyan Rift Volcanic Province of the broader Eastern Africa Volcanic Regions. Situated at 0.92° N, 36.18° E in the Northern Hemisphere, the volcano lies within a tropical climate zone. With a summit elevation of 1,697 meters above sea level, Paka is a moderately sized peak that remains accessible to hikers and researchers for much of the year. The volcanic landform is characterized as a shield, which describes the physical shape and structure of the volcanic edifice as observed from the surface.

Geological Context

Paka is situated along a rift zone, where tectonic plates are pulling apart. As the crust thins and fractures, magma rises to fill the gap, creating volcanic activity. Rift volcanism typically produces more fluid lava flows rather than explosive blasts, which means communities near Paka in Kenya generally face slower-moving hazards like lava flows and ground fissures rather than sudden pyroclastic events. However, rift volcanoes can still generate significant ash emissions and gas releases that affect local air quality. The dominant rock type is trachyte / trachydacite, an intermediate to silica-rich volcanic rock. This composition typically produces more viscous magma, leading to more explosive eruptions with ash columns and pyroclastic flows. Andesitic and dacitic magmas build pressure before erupting, which is why volcanoes with this rock chemistry are often associated with Plinian-style eruptions that can send ash tens of kilometers into the atmosphere and disrupt aviation across entire regions.

Eruption History Summary

Paka has 1 recorded eruption in the geological database, spanning from 7550 BCE to 7550 BCE. The most powerful recorded event was a cataclysmic eruption with ash columns reaching the stratosphere in 7550 BCE, reaching VEI 4 on the Volcanic Explosivity Index.

Significance

With a maximum recorded VEI of 4, Paka has demonstrated the capacity for significant explosive eruptions that can impact regional aviation, agriculture, and communities tens of kilometers from the summit. VEI 4 eruptions produce ash columns reaching 15-25 kilometers into the atmosphere.

GVP Reference Summary

The dominantly Pleistocene Paka shield volcano in the Gregory Rift contains a small 1.5-km-wide summit caldera. Eruption of large volumes of trachytic pyroclastic rocks around the end of the Pleistocene and the beginning of the Holocene formed a NW-trending ridge of pyroclastic cones across the summit region; collapse of this area formed the summit caldera and associated craters. A second large crater SE of the caldera is 0.5 x 1 km wide and contains a pumice cone. The summit caldera is narrowly breached on the N side, which has funneled post-caldera lava flows in this direction. The three youngest post-caldera pyroclastic cones on the NE flank may be only a few hundred years old. A series of viscous trachytic lava flows were erupted from vents on the lower flanks. Young fissure-fed basalts were also erupted to the S, between Paka and Korosi volcanoes. Surficial geothermal activity is widespread at Paka, both within the summit caldera and on extensive portions of the N flank.

— Smithsonian Institution, Global Volcanism Program