Surface‐wave tomography from ambient seismic noise of accelerograph networks in southern Korea

Abstract

An efficient and robust cross‐correlation technique for estimation of surface wave Green's function between two locations is applied to a set of ambient noise data recorded by accelerograph networks in the southern Korea. We have estimated 1843 group velocities of Rayleigh waves in the period band of 2–4 seconds from correlation pairs of 91 accelerograph stations. Relatively dense and uniform coverage of the pairs provides us with high‐resolution tomographic image of surface‐wave group velocities in the region. The resulting group‐velocity distribution correlates well with the characteristic features of geological map of the region, displaying low velocities for the sedimentary basins and regions of volcanic and metasedimentary rocks, and high velocities for the regions where granitoid basement rocks outcrop. The short‐period information from the accelerograph network can enhance resolution of the subsurface structures at depths within a few kilometers, which may be predominantly responsible for simulation results of strong ground motions.

Surface wave tomography on a large-scale seismic array combining ambient noise and teleseismic earthquake data

“…Ambient noise tomography has mainly been applied to surface waves, has extended analysis to shorter periods (<20 s) than from traditional earthquake tomography, and has provided higher resolution constraints on the structures of the crust and uppermost mantle. Currently, ambient noise tomography has been applied around the world to study crustal and uppermost structures; for example, Shapiro et al (2005), Moschetti et al (2007), Bensen et al (2008), Liang and Langston (2009) in US; Kang and Shin (2006), Cho et al (2007), Fang et al (2010), Li et al (2009), Yang et al (2010, Yao et al (2006Yao et al ( , 2008 in Asia; and Villaseñor et al (2007) in Europe; Arroucau et al (2010), Behr et al (2010), Lin et al (2007), Saygin and Kennett (2010) in New Zealand and Australia, and so on.…”

Determining the Orientations of Broadband Stations in South Korea using Ambient Noise Cross-correlation

“…두 개의 지진계에 기록된 배경잡음 의 교차상관으로부터 두 관측소 사이를 전파하는 레일리 파를 추출할 수 있다는 사실은 이미 수 많은 연구에서 증명 되었다 (e.g., Shapiro, 2004;Bensen et al, 2007;Lin et al, 2008;Kang and Shin, 2006 (Fig. 2).…”

Stationary phase approximation in the ambient noise method revisited

“…This method was first reported in ultrasonic experiments Lobkis, 2001, 2002) and then has been widely applied to crustal seismology to get high resolution surface wave tomography (Shapiro and Campillo, 2004;Shapiro et al, 2005). The scales of studied regions range from regional Kang and Shin, 2006;Yao et al, 2006;Villasenor et al, 2007;Cho et al, 2007) to continental (Yang et al, 2006). However, there are still a lot of controversies about why cross correlation of ambient seismic noise leads to Green's function.…”