Earthquakes, Solar Activity, and Background Atmosphere: in search of their association

The role of solar activity in the growth of an earthquake (EQ) is the topic of study here, focussing on the correlation & distribution function between global EQ events of M ≥ 4.5 and solar parameters covering seven cycles from 18 to 24. The analysis modes are in two steps: (i) EQ events in a total of all cycles taken under study and solar role on their growth; and (ii) EQ events filtered for a High Solar Active (HSA) and a Low Solar Active (LSA) years for each individual cycle & the respective contribution of solar strength to their occurrences. The paper presents the observation by drawing a relation between EQ event ratio during LSA and HSA year, i.e., EQ LSA /EQ HSA with the corresponding Rz ratio of the years, an approach adopted to reduce any bias/errors that arise on availability of more EQ data as year advances. The analysis offers a negative cum complex distribution with more EQ cases at 60–70% below the peak Rz when strong solar ambiances are observed to inhibit the growth of severe EQ events. The overall correlation analyses between Rz, geomagnetic indices like Kp/DST, and EQ-events of different magnitudes also provided a conclusion that solar ambiances play a complicated role in the growth process of an EQ. These observations are discussed by invoking the Forbush effect along with the possible contribution of atmospheric variabilities like global temperature, lithosphere heat content, and anthropogenic components.