Assessment of natural radioactivity level before and after a mud-volcano eruption: A study from Piparo mud-volcano, Trinidad and Tobago.

The present study was conducted in the Piparo mud-volcano, which is situated in the central part of the island of Trinidad, is geologically connected with the Central Fault Range Zone (CFRZ). This fault zone is a neotectonic (active) strike-slip fault system and an extension of the Andes Mountain chain. This study was aimed at detecting the possible gamma radiation level in Piparo MV after its eruption in September 2019 and finding the change in the ambient radiation level after that eruption. To achieve this aim, gamma radiation data were collected for 6 months (three times at 3 months interval) after this eruption. As a pilot study, gamma radiation measurements were measured with the help of a portable Geiger Muller counter from 32 locations. Radiation levels were nearly 2 times higher than the average background levels in the country indicating Piparo mud-volcano could have controlled the elevated radiation levels in the area. Good correlations were also found between elevated radiation in the northern and western sides of the main crater and presence of auxiliary craters in the same sides. Previous studies reported that the northern side of the crater was more active, and the present study also supported their observation. Good correlation (with coefficient >0.9) indicates that these radioactivity values might be syngenetic. Continuous release and slow reduction of radiation levels (only 13% over 6 months) may indicate a continuous activity in Piparo mud-volcano and may support CRFZ as a creep fault.