Rupture Process of the 1995 Antofagasta Subduction Earthquake (M w = 8.1)

Carlo, Debra L.; Lay, Thorne; Ammon, Charles J.; Zhang, Jiajun

doi:10.1007/978-3-0348-8679-6_13

Cited by 14 publications

(36 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For example, for dip‐slip earthquakes, waves radiated from one patch are reflected and can partially cancel the waves radiated from a different patch. These interference effects can cause a trade‐off between the inferred depth of the fault slip and the source time function of the slip [e.g., Christensen and Ruff , 1985], such that the along‐strike resolution is generally better than the downdip resolution when only teleseismic data are used [e.g., Carlo et al , 1999]. …”

Section: Data Usedmentioning

confidence: 99%

Distribution of slip from 11 M_w > 6 earthquakes in the northern Chile subduction zone

Pritchard

Simons

2006

J. Geophys. Res.

View full text Add to dashboard Cite

We use interferometric synthetic aperture radar, GPS, and teleseismic data to constrain the relative location of coseismic slip from 11 earthquakes on the subduction interface in northern Chile (23°–25°S) between the years 1993 and 2000. We invert body wave waveforms and geodetic data both jointly and separately for the four largest earthquakes during this time period (1993 Mw 6.8; 1995 Mw 8.1; 1996 Mw 6.7; 1998 Mw 7.1). While the location of slip in the teleseismic‐only, geodetic‐only, and joint slip inversions is similar for the small earthquakes, there are differences for the 1995 Mw 8.1 event, probably related to nonuniqueness of models that fit the teleseismic data. There is a consistent mislocation of the Harvard centroid moment tensor locations of many of the 6 < Mw < 8 earthquakes by 30–50 km toward the trench. For all models, the teleseismic data are better able to resolve fine details of the earthquake slip distribution. The 1995 earthquake did not rupture to the maximum depth of the seismogenic zone (as defined by the other earthquakes). In addition to the above events, we use only teleseismic data to determine the rupture characteristics of four other Mw > 6 earthquakes, as well as three Mw > 7 events from the 1980s. All of these earthquakes appear to rupture different portions of the fault interface and do not rerupture a limited number of asperities.

show abstract

Section: Data Usedmentioning

confidence: 99%

Distribution of slip from 11 M_w > 6 earthquakes in the northern Chile subduction zone

Pritchard

Simons

2006

J. Geophys. Res.

View full text Add to dashboard Cite

show abstract

“…A M w = 7.5 event broke below the center of the 1995 slip, followed by a M w = 7.2 down dip event of the southern region in 1988. In 1998 an M w = 7.0 event occurred down dip of the northern half of the 1995 event [ Dziewonski et al , 1997; Carlo et al , 1999], which is probably related to the Antofagasta main shock.…”

Section: Introductionmentioning

confidence: 99%

Rapid postseismic transients in subduction zones from continuous GPS

et al. 2002

View full text Add to dashboard Cite

[1] Continuous GPS time series from three of four recently measured, large subduction earthquakes document triggered rapid postseismic fault creep, representing an additional moment release upward of 25% over the weeks following their main shocks. Data from two M w = 8.0 and M w = 8.4 events constrain the postseismic centroids to lie down dip from the lower limit of coseismic faulting, and show that afterslip along the primary coseismic asperities is significantly less important than triggered deep creep. Time series for another M w = 7.7 event show 30% postseismic energy release, but here we cannot differentiate between afterslip and triggered deeper creep. A fourth M w = 8.1 event, which occurred in the broad Chilean seismogenic zone, shows no postseismic deformation, despite coseismic offsets in excess of 1 m. For the three events which are followed by postseismic deformation, stress transferred to the inferred centroids (at 34, 60, and 36 km depths) by their respective main shock asperities increased reverse shear stress by 0.5, 0.8, and 0.2 bar with a comparatively small decrease in normal stress (0.01 bar), constraining the Coulomb stress increase required to force slip along the metastable plate interface. Deep triggered slip of this nature is invisible without continuous geodesy but on the basis of these earthquakes would appear to constitute an important mode of strain release from beneath the seismogenic zones of convergent margins. These events, captured by some of the first permanent GPS networks, show that deep moment release is often modulated by seismogenic rupture updip and underscore the need for continuous geodesy to fully quantify the spectrum of moment release in great earthquakes.

show abstract

“…Previous studies (e.g., Carlo et al, ; Pritchard et al, ) suggested that there is no simple relationship between aftershocks and the slip distribution for this event and that the aftershock occurrence is likely related to stresses induced by postseismic rather than coseismic deformation. However, for our slip distribution, most aftershocks are located near the edges of coseismic large‐slip regions (Figure ), particularly the larger events that have focal mechanisms similar to the mainshock.…”

Section: Inversion Resultsmentioning

confidence: 79%

“…They do not show prediction of the early coda reverberations. Carlo et al () inferred a fairly smooth rupture with three embedded subevents, also finding that most of the slip occurred in the first 120 km or so. Their model did not replicate the normal fault subevent near the trench inferred by Delouis et al (), but they also could not fit the late P waves well with a thrust fault subevent.…”

Section: Inversion Resultsmentioning

confidence: 98%

Shallow Megathrust Slip During Large Earthquakes That Have High P Coda Levels

Zhen-bin

Lay

2020

JGR Solid Earth

Self Cite

View full text Add to dashboard Cite

Determining the up-dip extent of slip during large megathrust earthquakes is important for understanding tsunami generation, potential for subsequent failure of the shallow megathrust, and plate contact depth-varying frictional properties. Recent measurements of early P coda amplitudes relative to direct P signals for the period range 7 to 15 s find high P coda /P ratios for many events with finite-fault rupture models that have slip extending to near deep trenches, resulting in enhanced pwP (water-reverberation) generation. However, some events with high P coda /P measures have finite-fault model solutions that vary in, or lack, shallow slip. We reexamine six large megathrust earthquakes with unexplained high P coda /P ratios (30 for slip models with depth-varying dip and varying bathymetry, adjusting kinematic parameters to better allow for the possibility of late shallow slip with associated strong pwP excitation. We confirm that modest patchy late shallow slip (~1 to 3 m) occurred near the trench for the 1995 and 2003 events, accounting for observed high P coda levels and minor tsunamis. The 2009 event appears to have minor shallow slip, whereas the 1996, 2002, and 2015 events do not; their coda amplitudes are likely enhanced by early aftershocks. Refined modeling of the later stages of large megathrust ruptures, guided by P coda levels, improves resolution of the up-dip limit of co-seismic slip.

show abstract

Rupture Process of the 1995 Antofagasta Subduction Earthquake (M w = 8.1)

Cited by 14 publications

References 32 publications

Distribution of slip from 11 M_w > 6 earthquakes in the northern Chile subduction zone

Distribution of slip from 11 M_w > 6 earthquakes in the northern Chile subduction zone

Rapid postseismic transients in subduction zones from continuous GPS

Shallow Megathrust Slip During Large Earthquakes That Have High P Coda Levels

Contact Info

Product

Resources

About

Rupture Process of the 1995 Antofagasta Subduction Earthquake (M w = 8.1)

Cited by 14 publications

References 32 publications

Distribution of slip from 11 Mw > 6 earthquakes in the northern Chile subduction zone

Distribution of slip from 11 Mw > 6 earthquakes in the northern Chile subduction zone

Rapid postseismic transients in subduction zones from continuous GPS

Shallow Megathrust Slip During Large Earthquakes That Have High P Coda Levels

Contact Info

Product

Resources

About

Distribution of slip from 11 M_w > 6 earthquakes in the northern Chile subduction zone

Distribution of slip from 11 M_w > 6 earthquakes in the northern Chile subduction zone