Effect of tidal triggering on seismicity in Taiwan revealed by the empirical mode decomposition method

Abstract

Abstract. The effect of tidal triggering on earthquake occurrence has been controversial for many years. This study considered earthquakes that occurred near Taiwan between 1973 and 2008. Because earthquake data are nonlinear and non-stationary, we applied the empirical mode decomposition (EMD) method to analyze the temporal variations in the number of daily earthquakes to investigate the effect of tidal triggering. We compared the results obtained from the nondeclustered catalog with those from two kinds of declustered catalogs and discuss the aftershock effect on the EMD-based analysis. We also investigated stacking the data based on inphase phenomena of theoretical Earth tides with statistical significance tests. Our results show that the effects of tidal triggering, particularly the lunar tidal effect, can be extracted from the raw seismicity data using the approach proposed here. Our results suggest that the lunar tidal force is likely a factor in the triggering of earthquakes.

New insights and best practices for the successful use of Empirical Mode Decomposition, Iterative Filtering and derived algorithms

“…We have found several studies published in the literature where signals containing spikes or jumps are not carefully handled 38,[109][110][111][112] .…”

“…The proper identification of spikes position in signals has been already studied in the literature, for instance in 113,114 , and for the jumps the so called essentially non-oscillatory (ENO) technique was developed in computational fluid dynamics to capture shock positions 25,115 , and it can be adopted in this context. If on the one 110 . Left: From top to bottom, the first six IMFs of the non-stacked data of the number of daily earthquakes from the Taiwanese catalog for events of magnitude M L ≥ 3.0 from 1978 to 2008.…”

“…The authors want to thank Haomin Zhou (Georgia Tech) and Emanuele Papini (University of Florence) for the interesting discussions and all the advises they gave on the topic. We thank the authors of the work 110 for sharing with us their data sets that we used in "Real life example".…”

Acoustic Emission/Seismicity at Depth Beneath an Artificial Lake after the 2011 Tohoku Earthquake

“…The triggering of earthquakes is sensitive to changes in stress when conditions are critical for shear slip. For example, tidal changes are a likely factor in triggering certain seismic events [20] even though the stress change due to earth tides is no greater than about 10 3 Pa [21]. On the other hand, the water level of Lake Okura changes by about 20 m, which corresponds to a change in overburden pressure of 200 × 10 3 Pa.…”

Earth’s Outgoing Longwave Radiation Variability Prior to M ≥6.0 Earthquakes in the Taiwan Area During 2009–2019

“…Identifying earthquake precursors has often been considered a useful method to mitigate seismic disasters. In the past few decades, a wide variety of earthquake precursors have been investigated for Taiwan, including gas and fluid geochemical changes (Liu et al, 1985;Song et al, 2003Song et al, , 2006Chyi et al, 2005;Fu et al, 2005Fu et al, , 2008Fu et al, , 2009Fu et al, , 2017aYang et al, 2005Yang et al, , 2006Kuo et al, 2006Kuo et al, , 2010Walia et al, 2009Walia et al, , 2013Kumar et al, 2015;Fu and Lee, 2018), gamma-ray monitoring (Fu et al, 2015(Fu et al, , 2019, groundwater levels (Chia et al, 2001;Wang et al, 2001;Lai et al, 2010;Chen et al, 2013bChen et al, , 2015c, borehole strain changes (Liu et al, 2009;Canitano et al, 2015Canitano et al, , 2017Hsu et al, 2015), seismicity changes (Chen et al, 2005(Chen et al, , 2006Wu and Chiao, 2006;Wu and Chen, 2007;Wu et al, 2008;Lin, 2009;Kawamura et al, 2014), tidal variations (Lin et al, 2003;Chen et al, 2012), GPS observations (Chen et al, 2013c(Chen et al, , 2015b, lightning activity (Liu et al, 2015),...…”