how old is it in terms of volcanic activity?
UNANSWERABLE
what type of eruption does nevado del ruiz produce The volcano usually generates Vulcanian to Plinian eruptions can you explain the first one? It is a type of volcanic eruption characterized by a dense cloud of ash-laden gas exploding from the crater and rising high above the peak and what kind of material does the second one eject? It ejects  Pumice where is the above mentioned volcano located? It is located on the border of the departments of Caldas and Tolima in Colombia, about west of the capital city Bogotá
wiki:12124975
Nevado del Ruiz [SEP] Introduction
The Nevado del Ruiz (), also known as La Mesa de Herveo () is a volcano located on the border of the departments of Caldas and Tolima in Colombia, about west of the capital city Bogotá. It is a stratovolcano composed of many layers of lava alternating with hardened volcanic ash and other pyroclastic rocks. Volcanic activity at Nevado del Ruiz began about two million years ago, since the Early Pleistocene or Late Pliocene, with three major eruptive periods. The current volcanic cone formed during the present eruptive period, which began 150 thousand years ago. The volcano usually generates Vulcanian to Plinian eruptions, which produce swift-moving currents of hot gas and rock called pyroclastic flows.