Brief Communication: Correlation of global earthquake rates with temperature and sunspot cycle

Abstract

Abstract. We studied the complex and non-stationary records of global earthquake employing the robust statistical and spectral techniques to understand the patterns, processes and periodicity. Singular Spectral Analysis (SSA) and correlation methods are used to quantify the nature of principle dynamical processes of global annual earthquake rates. The SSA decomposes the principle component of earthquake rates (first mode), which suggests that there is a linear increase in the yearly earthquake number from 1975 to 2005 accounting for 93% variance and may be identified with the earth's internal dynamical processes. Superimposed on this monotonic trend, there is an 11 years cyclic variation (second and third modes) accounting for 5% variance, which may corresponds to the well-known solar cycle. The remaining 2% higher order fluctuating components appears to be associated with artificial recharge and natural triggering forces (reservoir, tidal triggering etc.). The correlation study indicates that there is strong positive and negative correlation among the global earthquake rates with surface air temperature and sunspot numbers respectively. Interesting coupling mechanisms do exist, in which atmospheric circulations perturbed by the abrupt temperature variability might change the torques/momentum of inertia (earth's angular momentum) of the earth and thereby may offer the required inputs to trigger earthquake activities at the "critical phases".

On the Origin of ULF Magnetic Waves Before the Taiwan Chi-Chi 1999 Earthquake

“…This correlation between the solar wind speed values and the presence/absence of the magnetic fluctuation in Taiwan, along with the previous Test 5, confirms that an external agent controls the sub-ULF magnetic fluctuations in Taiwan during 7 months before the Chi-Chi 1999 earthquake. This finding is consistent with recent statistical results (Gulyaeva, 2014;Rekapali, 2014;Anagnostopoulos et al, 2021) Furthermore, it worths noting that the analysis of polarization (the ratio of vertical magnetic field component Z to the horizontal component G), that the polarization (Z/G) showed a significant enhancement for 2 months before the Chi-Chi earthquake. Akinaga et al (2001) pointed out that this temporal evolution of polarization seems be associated with the Chi-Chi earthquake.…”

“…Anagnostopoulos et al (2021) performed various statistical studies based on solar, space and seismological data between 1900 and 2017 and we also found strong evidence that both the great earthquakes as well as high global seismic energy release occur during the rising and the decay phase of SC as well as at specific times of the maximum solar cycle phase with temporal (# months) weak solar activity. In general, the analysis of monthly averaged solar sunspot number (SSN) confirms a systematic and significant negative correlation of the seismic activity with the SSN (Gulyeva, 2014;Rekapali, 2014;Anagnostopoulos et al, 2021).…”

“…During these long time periods, CIRs can transfer much more energy into the magnetosphere than a single CME (Tsurutani et al, 2006). For this reason high seismicity is well related with the presence of CIR-induced geomagnetic events around the minimum phase of the solar cycle (Gulyaeva, 2014;Rekapali, 2014;Anagnostopoulos et al, 2021). Other external sources, as for instance CME-driven events or Earth tides, possibly make some minor contribution to the preparation process of great earthquakes, but there is not such significant observational evidence.…”

Temporal Variation and Statistical Assessment of the b Value off the Pacific Coast of Tokachi, Hokkaido, Japan

“…Previous studies have suggested that there is a correlation between global earthquake rates and sunspot cycles [ 27 , 28 , 29 ]. In order to examine whether the long-term b value variation observed in Hokkaido is a local phenomenon governed by regional stress evolution or a global phenomenon related to solar activities, we performed a test in the Tokai area, which is far from Hokkaido.…”

“…It is interesting to find a similar decrease of b values at large distances for Hokkaido and Sumatra around the year 2000. Some previous studies indicate that there is a correlation between space weather and seismicity: there is a higher seismicity during the rising and the decay of the solar cycle [ 27 , 28 ]. One may think the decrease trend of the b value is a global effect associated with solar activities.…”