Preseismic anomalies in soil-gas radon associated with 2016 M 6.6 Meinong earthquake, Southern Taiwan

Abstract

Taiwan is tectonically situated in a terrain resulting from the oblique collision between the Philippine Sea plate and the continental margin of the Asiatic plate, with a continuous stress causing the density of strong-moderate earthquakes and regional active faults. The continuous time series of soil radon for earthquake studies have been recorded and some significant variations associated with strong earthquakes have been observed. Earthquake prediction is not still operative but these correlations should be added to the literature about seismo-geochemical transients associated to strong earthquakes. Rain-pore pressure related variations, crustal weakness at the studied faults system is consistent with the simultaneous radon anomalies observed. During the observations, a significant increase of soil radon concentrations was observed at Chunglun-T1 (CL-T1), Hsinhua (HH), Pingtung (PT), and Chihshan (CS) stations approximately two weeks before the Meinong earthquake (M L = 6.6, 6 February 2016) in Southern Taiwan. The precursory changes in a multi-stations array may reflect the preparation stage of a large earthquake. Precursory signals are observed simultaneously and it can apply certain algorithms the approximate location and magnitude of the impending earthquake.

Pre-seismic strain anomalies and coseismic deformation of Meinong earthquake from continuous GPS

“…A significant increase of soil radon concentrations GS52 120.65472 23.03402 -34.4 ± 2.3 -11.8 ± 1.3 -25.4 ± 3.0 GS53 120.39831 22.83998 -11.6 ± 1.7 -21.7 ± 1.6 14.5 ± 3.3 GS55 120.60224 22.85069 -11.9 ± 1.7 2.7 ± 0.9 -10.2 ± 4.1 GS56 120.60173 22.70388 -0.6 ± 1.7 -2.8 ± 1.0 -3.4 ± 3.4 GS74 120.45980 22.93916 -17.6 ± 2.5 -15.0 ± 1.6 43.9 ± 5.1 GS75 120.49412 22.88556 -10.3 ± 2.1 -11.8 ± 1. NAZI 120.32633 22.72824 -3.0 ± 2.0 -3.6 ± 1.7 -0.9 ± 4.6 NCKU 120.27581 22.93845 -26.1 ± 2.9 -8.5 ± 0.7 13.7 ± 5.7 NEMN 120.42008 22.90812 -27.5 ± 2.6 -30.2 ± 2.0 55.8 ± 4.6 PAOL 120.70287 23.10862 -19.9 ± 2.2 -13.0 ± 0.9 -8.0 ± 2.7 PTUN 120.45968 22.64985 1.2 ± 1.6 -3.2 ± 1.5 -1.0 ± 3.9 S012 120.48826 23.05947 -14.0 ± 2.4 1.9 ± 0.7 -1.3 ± 4.7 S106 120.33409 23.05079 -18.4 ± 1.4 9.4 ± 0.8 16.4 ± 5.7 S169 120.50331 22.94229 -17.9 ± 2.5 -6.6 ± 1.3 4.4 ± 3.5 S23R 120.60617 22.64498 -0.3 ± 1.9 -2.5 ± 1.0 -1.3 ± 4.2 SAME 120.29946 22.64763 1.0 ± 1.8 -3.2 ± 1.7 -2.0 ± 2.7 SAND 120.64064 22.71727 -2.9 ± 1.4 -2.6 ± 1. was also observed at several stations about two weeks before the Meinong earthquake in southern Taiwan (Fu et al 2017). From the high precision of continuous GPS data, an appreciable decrease in extension rate was also detected approximately 4 months before the Rueisuei earthquake (Fu et al 2016).…”

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),...…”

Assessment of Sensitivity Zone of Radon and Temperature Measurements in Study of Process of Tectonic Earthquakes Preparation

“…While using various methods of studying the changes in the geodynamic state of the Earth's crust, which allow in some cases predicting seismic [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] and volcanic [17][18][19][20][21][22] events, the question of their long-range action or spatial sensitivity arises.…”