Weibull distribution analysis of precursory time due apparent resistivity anomaly prior to earthquakes in the vicinity of multi-parametric geophysical observatory, Tezpur, India

Abstract

The apparent resistivity imaging at multiparametric geophysical observatory (MPGO), Ouguri Hills, Tezpur was carried out since 31st August, 2016 for fixed interval time of 3 days to investigate precursory signature prior to earthquake events. Anomalies in apparent resistivity prior to earthquake events are observed. The anomalies are not influenced by the rainfall activity in the region during the investigation period. We adopt Weibull distribution technique with observed apparent resistivity data to look for and revalidate the observations. The Weibull parameters, i.e. K and m are estimated to be 0.26 and 1.04, respectively. No precise relation between magnitude and earthquake precursory time is found. Simultaneously, an attempt has been made to establish a relation between the earthquake magnitude (M) and precursory time (T) and a relation between the earthquake precursory time (T) and distance of the earthquake (Δ) from the observation point. Weibull probability distribution indicate the probability of an earthquake occurrence exceeds the measure up to 80% (9 days) after the precursory signal is observed. A comparison of probability analysis ascertains a mean precursory time and its standard deviation.

Keywords

• earthquake
• resistivity
• precursor
• dilatancy
• weibull distribution