A first modeling of dynamic and static crustal strain field from near-field dilatation measurements: example of the 2013 $$M_w$$ M w 6.2 Ruisui earthquake, Taiwan

Abstract

We analyze the high-resolution dilatation data for the October 2013 M w 6.2 Ruisui, Taiwan, earthquake, which occurred at a distance of 15-20 km away from a SacksEvertson dilatometer network. Based on well-constrained source parameters (strike = 217 • , dip = 48 • , rake = 49 • ), we propose a simple rupture model that explains the permanent static deformation and the dynamic vibrations at short period (∼3.5-4.5 s) for most of the four sites with less than 20 % of discrepancies. This study represents a first attempt of modeling simultaneously the dynamic and static crustal strain using dilatation data. The results illustrate the potential for strain recordings of high-frequency seismic waves in the near-field of an earthquake to add constraints on the properties of seismic sources.

Testing the Influence of Static and Dynamic Stress Perturbations On the Occurrence of a Shallow, Slow Slip Event in Eastern Taiwan

“…Based on the analysis of 18 years of geodetic data (1992–2010) for the LVF which includes the large postseismic slip following the 2003 Chengkung earthquake (e.g., Y. J. Hsu et al, ), M. Y. Thomas et al () inferred that a major fraction (>80%) of the long‐term slip budget on the southern section of the LVF is the result of aseismic slip. The CRF, located on the western side of the valley, is a high‐angle reverse west‐dipping structure (Shyu et al, ), also capable of producing large earthquakes such as the October 2013 M w 6.2 Ruisui event (Canitano et al, , ).…”

“…Strainmeters are highly sensitive instruments with a precision better than 1 nanostrain (n ϵ ; i.e., less than 1 mm over a distance of 1,000 km) at a period 10 −2 –10 3 s. The Ruisui‐Chimei strainmeter network, in central LV, is composed of three borehole dilatometers and one 3‐component borehole strainmeter (Figure ). Sensors are installed in competent rocks at depths of 185 to 265 m and have recorded relevant seismic (e.g., Canitano et al, ) and environmental signals (Y. J. Hsu et al, ; Liu et al, ). SSNB 3‐component strainmeter can measure strain variations in three directions at 120° from each other, which allows monitoring of rock volume change (dilatation ϵ v ) and horizontal shear components ( γ 1 and γ 2 ; see Section S1 and Figure S1 in the supporting information for details).…”

“…Strainmeters are highly sensitive instruments with a precision better than 1 nanostrain (n ; i.e., less than 1 mm over a distance of 1,000 km) at a period 10 −2 -10 3 s. The Ruisui-Chimei strainmeter network, in central LV, is composed of three borehole dilatometers and one 3-component borehole strainmeter ( Figure 1). Sensors are installed in competent rocks at depths of 185 to 265 m and have recorded relevant seismic (e.g., Canitano et al, 2017) and environmental signals (Y. J. Hsu et al, 2015;Liu et al, 2009).…”

Seismicity Controlled by a Frictional Afterslip During a Small‐Magnitude Seismic Sequence (ML < 5) on the Chihshang Fault, Taiwan

“…It was established to support GPS observations with the aim of detecting fault slip transients along the fault as well as to record the short‐ to long‐term subsurface deformation. Strainmeters for continuous crustal strain monitoring are highly sensitive instruments with a precision better than 10 −9 (i.e., less than 1 mm over a distance of 1,000 km) at a period 10 −2 –10 3 s. Strainmeters established along the LVF allowed us to record and model relevant crustal signals such as large strain changes (a few hundred of nanostrain; n ε ) associated with typhoon passing (Hsu et al, ; Liu et al, ; Mouyen et al, ), coseismic static offsets (Canitano et al, ), near‐field dynamic strain (Canitano et al, ), and tidal shear strain (Canitano et al, ).…”

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),...…”