The 2010 M _w 8.8 Maule Megathrust Earthquake of Central Chile, Monitored by GPS

Abstract

Large earthquakes produce crustal deformation that can be quantified by geodetic measurements, allowing for the determination of the slip distribution on the fault. We used data from Global Positioning System (GPS) networks in Central Chile to infer the static deformation and the kinematics of the 2010 moment magnitude (M(w)) 8.8 Maule megathrust earthquake. From elastic modeling, we found a total rupture length of ~500 kilometers where slip (up to 15 meters) concentrated on two main asperities situated on both sides of the epicenter. We found that rupture reached shallow depths, probably extending up to the trench. Resolvable afterslip occurred in regions of low coseismic slip. The low-frequency hypocenter is relocated 40 kilometers southwest of initial estimates. Rupture propagated bilaterally at about 3.1 kilometers per second, with possible but not fully resolved velocity variations.

Comparison of postseismic afterslip models with aftershock seismicity for three subduction-zone earthquakes: Nias 2005, Maule 2010 and Tohoku 2011

“…However, south of 35.5 • S the slip of still a significant number of events exceeds the afterslip from the GPS in a region where largely aftershocks related to the plate interface were located (Lange et al 2012). Agurto et al (2012) compared the seismic slip of the first 12 d with the TA model from Vigny et al (2011) and similarly found regions where the slip from seismicity exceeds the TA model. As the TA on the plate interface must be inferred from observations of surface displacements the TA model is severely limited in spatial resolution (Hetland & Simons 2010), particularly offshore, and effectively averages small slip patches like those caused by moderate and even strong events over larger regions.…”

“…3) and by its location between the two co-seismic slip maxima of the Maule 2010 event (e.g. Vigny et al 2011).…”

“…A dense network of continuous GPS (cGPS) stations was installed in the Maule region after the main shock (Bevis et al 2010;Vigny et al 2011) densifying the existing cGPS network (Bevis et al 2001;Ruegg et al 2009;Vigny et al 2009). The large number of GPS stations allows an unprecedented spatio-temporal resolution of the rapidly time-varying postseismic response in near, medium and far-fields following a large subduction earthquake.…”

Análise de deformação por variação do geopotencial: estudo de caso para o terremoto maule (Mw 8,8) com base em dados mensais da missão Grace

“…2011. Tais plataformas possibilitam igualmente o tratamento de aspectos relacionados com a recuperação das principais características da distribuição de deformações e falhamentos VIGNY et al, 2011;DELOUIS et al, 2010). No entanto, tais ferramentas limitam-se a aspectos morfológicos de natureza geométrica e/ou relativa.…”

Improved GPS‐based coseismic displacement monitoring using high‐precision oscillators

“…The epicenter of the main shock was located approximately 100 km to the north of the station offshore in the Maule region in central Chile. The epicenter of the smaller earthquake that occurred 90 min after the main shock was approximately 200 km southwest of the observation station (Figure 2) [Vigny et al, 2011;Bedford et al, 2013].…”