Hydrogeochemistry of volcanic hydrogeology based on cluster analysis of Mount Ciremai, West Java, Indonesia

Hydrogeochemical analysis has been conducted on 119 spring locations to portray volcanic hydrogeological system of Mount Ciremai, West Java, Indonesia. Cluster analysis on 14 parameters has extracted three clusters. Cluster 1 (112 springs) is distinguished by normal temperatures, low TDS, EC, and high bicarbonate concentrations. Cluster 2 (five springs) has moderately high temperature, TDS, EC, and high concentration of chloride. Cluster 3 (two springs) exhibits high temperature, anomalous high TDS, EC, and chloride concentration. Three hydrogeological systems have been pictured based on the 3 clusters consecutively. The 1st system is developed in shallow unconfined aquifer, with domination of high bicarbonate (4.2 me/L) meteoric water. The 2nd system is predominated with mixing processes, between groundwater in unconfined aquifer and hot groundwater from deeper aquifers. The 3rd system is primarily dominated by groundwater flow from deep formation. The hot – deep seated groundwater flow also carries mud particles. It has anomalous high TDS (>1000 mg/L), EC (515 μS/cm), and chloride (99 me/L) from interaction between groundwater with clay formations, interpreted as Kaliwangu Formation.