What geological condition creates the geothermal reservoir at Olkaria?

The Kenyan portion of the East African Rift System constitutes one of the most prolific geothermal prospects on the planet. Crustal thinning associated with divergent plate tectonics brings subterranean magma chambers into close proximity with permeable volcanic aquifers. At the Olkaria geothermal field near Lake Naivasha, deep production wells tap pressurized subterranean reservoirs exceeding . The superheated geothermal steam expands through multistage turbines to generate baseload electricity with near-zero greenhouse gas emissions. Unlike hydroelectric facilities whose output fluctuates erratically during prolonged drought seasons in the Horn of Africa, geothermal plants provide steady, climate-independent electricity, currently supplying over forty percent of Kenya's national grid.

Answer and explanation

Correct answer: D. Divergent tectonic plate thinning bringing magma close to permeable aquifers.

  1. Step 1: Examine the tectonic setting of Kenya's Great Rift Valley: it is a continental divergent boundary where the African continent is actively rifting into two plates.
  2. Step 2: Identify the geothermal mechanism: crustal extension and thinning allow molten magma to rise close to the Earth's upper crust, heating groundwater trapped in deep, permeable volcanic rock aquifers. Thus, the condition is divergent tectonic plate thinning bringing magma close to permeable aquifers.
Answer
Divergent tectonic plate thinning bringing magma close to permeable aquifers.

Practise more Grammar, Comprehension and Literary Skills.

Free questions with an explanation for every one, and full timed Kenya KCSE mock tests.

All Grammar, Comprehension and Literary Skills questionsTake a mock test

More Grammar, Comprehension and Literary Skills questions