What is Pleistocene?
Pleistocene meaning The Pleistocene is the time period between about 10,000 years before present and about 1,650,000 years before present. As a descriptive term applied to rocks or faults, it marks the period of rock formation or the time of most recent fault slip, respectively. Faults of Pleistocene age may be considered active though their activity rates are commonly lower than younger faults.
reference: USGS – Earthquake Glossary