Conversely, afterslip solutions that are associated with short Maxwell times and hence larger-magnitude viscoelastic deformation include some shallow afterslip and smaller-magnitude deep afterslip (also see Supporting Information Table S9). Dashed lines show the slab contours every 20km. 2002). The vertical components at continuous stations INEG, CUVA, UAGU and TNZA were all discarded due to non-tectonic subsidence at each site that we attribute to groundwater withdrawal. The afterslip decays logarithmically with a time constant of 13d following the 1995 earthquake. (c) Campaign sites. 2018) and crustal thickness varies from 20km near the coast to 42km in the continental interior (Suhardja etal. In the case of COLI, the percentages are 10.0 percent and 18.5 percent). Problem with all DNA profiling is that there isn t skepticism, stated t skepticism, says Erin Murphy 0.1 mm s1 there isn t held line! The displacements shown in each panel were determined using the mantle Maxwell time given in the lower right corner of each panel. The velocity ellipses show the 2-D, 1- uncertainties. Positions are progressively shifted to the right to help visualization. Please note: Oxford University Press is not responsible for the content or functionality of any supporting materials supplied by the authors. The blue line delimits the earthquake aftershock area (Pacheco etal. 20). (b) Continuous sites installed near the Nevado de Colima volcano. 2013); and 0.81.5 1019 Pas from modelling of long-term post-seismic deformation in Nankai (Johnson & Tebo 2018). At present, the motions at sites in western Mexico are a superposition of steady interseismic strain accumulation due to frictional locking of the Mexico subduction interface and transient surface deformations from post-seismic afterslip and viscoelastic rebound triggered by the 1995 and 2003 earthquakes. Late-Night Drinking. 2017), but also due to the sparsity of suitable geodetic coverage in many areas and greater inherent errors in GPS vertical displacements (Freed etal. These estimates would contribute to a better understanding of the range of fault slip phenomena that accommodate the long-term plate convergence along the JCSZ and their locations on the subduction interface. Figure S15: TDEFNODE slip solutions for the 1995 ColimaJalisco earthquake afterslip (integrated over the 1995.772020.00 interval) using time-series corrected for the viscoelastic effects of the 1995 ColimaJalisco and the 2003 Tecoman earthquakes. Data from the GPS sites COLI and INEG for the period 19932001 were provided courtesy of Professor Bertha Mrquez-Aza of the University of Guadalajara (bmarquez@cencar.udg.mx). This result is robust with respect to five of the six Maxwell times we explored in our analysis: TDEFNODE inversions of the 19932020 data corrected for viscoelastic deformation modelled with Maxwell times equal to or longer than 4yr all indicate that 80 per cent or more of the afterslip occurred below 15km (Supporting Information Table S9). 2013). EQ: earthquake. 2019, and figs 11 and 16). The seismicity suggests distributed shear across a diffuse RiveraCocos plate boundary (DeMets & Wilson 1997). The principal difference between the 2003 earthquake co-seismic and afterslip solutions (Figs14a andb, respectively) is that the latter is located 1020km farther downdip than the former. RT: Rivera transform. (2002) show that a combination of fault afterslip and viscoelastic rebound are needed to account for the observed transient post-seismic deformation. This result, and the reversal of vertical motions with respect to the co-seismic direction, strongly indicate that the fault afterslip was focused downdip of the co-seismic rupture (compare Figs14a andb). 9(a). 14b). The interval used for the inversion is shown in each panel. As an example, continuous GPS measurements at site COLI onshore from the 1995 and 2003 earthquakes (inset map in Fig. Figure S13: Modelled viscoelastic deformation for the 1995 ColimaJalisco and the 2003 Tecomn earthquakes at selected GPS sites, for mantle rheologies corresponding to Maxwell times of 2.5 (blue), 15 (red) and 40yr (green). For each starting model, we calculated synthetic 3-D velocities at the GPS sites and perturbed the synthetic velocities with random noise of 1mm yr1 (1-sigma) for the horizontal components and 2mm yr1 for the vertical. \end{eqnarray*}$$, $$\begin{equation*} The estimated horizontal co-seismic offsets are largely consistent with those predicted by Schmitt etal. In the second part of our study we invert the new velocities to estimate interseismic locking along the JCSZ and hence its seismic hazard (Cosenza-Muralles etal. Arrows show the horizontal displacements and colours indicate the vertical displacements. The afterslip solutions for both earthquakes suggest that most afterslip coincided with the rupture areas or occurred farther downdip and had cumulative moments similar to or larger than the co-seismic moments. 2015; Freed etal. Fig. The yellow patch is the total estimated aftershock area of the 1932 June 3 and 18 earthquakes (Singh etal. 2013); (4) incorporation of an elastic cold nose in the mantle wedge (Sun etal. 2018) at the Instituto de Geofsica-Universidad Nacional Autnoma de Mxico (UNAM). (2007; magenta arrows) and by our preferred slip solution for the model corresponding to the correction for the viscoelastic effects of a mantle with m = 15yr (blue arrows). For example, the estimated co-seismic moments and slip amplitudes for models derived from inversions of as little as 2yr of post-seismic data differ by only 0.12.3 percent from those for the preferred model and by only 1.85.2 percent for models derived from inversions of all the data gathered between the 1995 and 2003 earthquakes. Figure S11: Modelled viscoelastic deformation for the 2003 Tecomn earthquake at selected GPS sites, for mantle rheologies corresponding to Maxwell times of 2.5 (blue), 15 (red) and 40yr (green). Based on results from static modelling of the newly estimated interseismic motions (CM21-II), we adopt a best viscosity of 1.9 1019 Pas (m = 15yr). Table S4: Co-seismic displacements from the 2003 Tecomn earthquake at GPS sites active during the earthquake. 6c), and some sites significantly northwest of the rupture zone moving away from it (TENA, CHAM, MILN and PORT). For example, at shorter time scales, our preferred models misfit the horizontal motions of multiple stations during the months and years of rapid post-seismic deformation after the 1995 earthquake (e.g. Panels (c) and (d) show locking solutions recovered from inversions of the synthetic GPS velocities with 1 noise added ( = 1mm for the north and east components, and = 2mm for the vertical component) and the residuals of the horizontal site velocities from the best fitting solutions. (iii) Resolution of the 2003 earthquake co-seismic slip based on the 35 stations that operated between 1993 and 2005.5 and with data after 2003 (Supporting Information Fig. In the Supporting Information, we describe results from a TDEFNODE inversion of the GPS position time-series assuming that fault afterslip was the source of all the observed transient post-seismic deformation (i.e. Eq. Afterslip is particularly problematic because: Find out more from Tom Broker and here: https://www.google.com/amp/s/ucrtoday.ucr.edu/38678/amp Select one: a. Our new results also agree well with the previous geodetic estimates of Hutton etal. Co-seismic subsidence is predicted at most sites, decreasing with distance from the large slip areas and transitioning to minor uplift at distances more than 170km inland from the coast (blue arrows in Fig. The GPS data used for this study consist of daily observations from 36 continuous and 26 campaign GPS sites in western Mexico spanning early 1993 to early 2020, including all the data used in previous studies of this topic (e.g. Five continuous stations, namely TNCM, TNLC, TNM2, MNZO and TNMR, were installed at the same locations of earlier discontinued stations: CHMC, GUFI, UCOL, MANZ and MMIG, respectively. Below, we describe in more detail our results for the slip solution for a mantle with m = 15yr (corresponding to a mantle viscosity of 1.89 1019 Pas). 2016). When it afterslip is particularly problematic because: particularly problematic because: Find out more from Tom Brocher and here: Select one.., etc fault slip ( afterslip ) estimates it could be anywhere from years! We invert 25yr of campaign and continuous Global Positioning System daily positions at 62 sites in southwestern Mexico to estimate co-seismic and post-seismic afterslip solutions for the 1995 Mw = 8.0 ColimaJalisco and the 2003 Mw = 7.5 Tecomn earthquakes, and the long-term velocity of each GPS site. (b) Vertical velocities. 2007). Any queries (other than missing material) should be directed to the corresponding author for the paper. 1998; Wang 2007). 14a) and the seismologic slip solutions referenced above is reinforced by the checkerboard test most applicable for the 2003 earthquake (Supporting Information Fig. 2004), and epicentres estimated by Yagi etal. Most figures were produced using Generic Mapping Tools software (Wessel & Smith 1991). Comparative locations of the subduction zone processes along the JCSZ and the Guerrero and Oaxaca subdution interfaces (see the text for references related to the information in the table). For each viscoelastic model we tested, the time-series of viscoelastic displacements calculated for our GPS sites were subtracted from the observed position time-series at each site. 20). Thin black lines represent 1- uncertainties. 14c and Supporting Information Table S8), particularly at inland locations. It is movement following an earthquake that continues to break pipes, aqueducts and other infrastructure for weeks and months. Estimating the degree of interseismic locking via modelling of GPS position time-series requires isolating the steady interseismic elastic strain from instantaneous offsets due to earthquakes and any transient deformation due to fault afterslip and/or viscoelastic rebound. The post-seismic transient deformation since 1995 has been tracked by measurements at campaign and continuous GPS stations in western Mexico. Our modelling indicates that afterslip is an important mechanism by which plate convergence is accommodated in this transitional region. 1 However, these figures do not include the marketing content online, in print, at the movies, in video games, or at school. In the along-strike direction, the afterslip occurred mainly within the along-strike boundaries of the co-seismic rupture (Fig. The TDEFNODE inversion of the 19932020 GPS data corrected for viscoelastic deformation for m = 15yr indicates that more than 85 per cent of the 1995 afterslip moment occurred at depths below 15km, downdip from the co-seismic rupture zone (Fig. (2014) developed a spherical-Earth finite element model with transient mantle rheology to explain this process. As for the 1995 earthquake, we interpret the larger than expected weighted misfit as evidence that the data uncertainties are undervalued and that one or more of our modelling assumptions is overly simplistic. The same TDEFNODE inversion indicates that afterslip from the 2003 earthquake was concentrated primarily along and directly downdip from the 2003 earthquake rupture zone (Fig. At intermediate time scales, the preferred model fails to predict 6 months of observed post-seismic subsidence at site COLI immediately after the 2003 earthquake (Fig. We also estimate the long-term velocities of all the GPS sites fully corrected for the co-seismic and post-seismic effects of the 1995 and 2003 earthquakes. 2001). \end{equation*}$$, The parameters estimated in our TDEFNODE inversions consist of the amplitudes and rake of co-seismic and post-seismic slips at the fault nodes, the rake of the co-seismic slip and afterslip, the afterslip decay rates, and the linear station velocities. 2006; Pea etal. Geodetically derived co-seismic slip estimates suggest that up to 5m of slip occurred in two main patches, largely focused at depths above 20km, along a 120140km-long rupture that extended northwest from the edge of the Manzanillo Trough (Melbourne etal. Superposing velocity vectors are shifted to the right to help visualization. Panels (c) and (d) respectively show the horizontal and vertical site motions predicted by the co-seismic and afterslip solutions from panels (a) and (b) at sites active during the earthquake for panel (c) and sites active between 1995 and 2003 for panel (d). 2012; Bedford etal. 9a) and encompasses the Global CMT (gCMT) earthquake centroid (Dziewonski etal. Our modelling illustrates both of these trade-offs. mantle viscosity, mantle-crust interface depth and afterslip decay time). Global distribution of earthquakes c. Glob Can promote or inhibit fault slip, particularly at the ruptured fault would take between six and 12 years complete. ] The wrms misfits range from 1.9 to 4.9mm in the horizontal components at the 36 continuous sites and 5.05.1mm at the 26 campaign sites. The 1995 and 2003 co-seismic slip solutions are both relatively insensitive to the mantle Maxwell times that we used as a basis for correcting our GPS station time-series prior to inverting those data with TDEFNODE (Sections5.1 and5.3). 14d). Modelled viscoelastic deformation for the 1995 ColimaJalisco earthquake at GPS sites active during the earthquake for mantle rheologies corresponding to Maxwell times of 2.5 (blue), 15 (red) and 40yr (green). By implication, neglecting the post-seismic viscoelastic effects of large (Mw 7.5) thrust earthquakes, such as the Mw = 8.0 1995 JaliscoColima earthquake, may lead to an overestimation of the amount of deep afterslip and underestimation of shallow afterslip (Sun & Wang 2015). Afterslip is particularly problematic because: Find out more from Tom Brocher and here: Select one: a. 14a) and also agrees with the seismologic slip solution of Quintanar etal. The latter two processes decay with different characteristic timescales after the earthquakes. Afterslip is particularly problematic because: Find out more from Tom Brocher and here: https://www.google.com/amp/s/ucrtoday.ucr.edu/38678/amp Select one: a. Our preferred time-dependent model for 1993.28 to 1999.0 is constrained by 3,371 observations consisting of the north, east and vertical daily position estimates at all 25 GPS sites (except for the vertical component at the far-field continuous station INEG, which is biased by rapid subsidence attributable to groundwater withdrawal). Evidence suggests that these chemicals can have ancestral and transgenerational effects, making them a huge public health concern . 1997; Hutton etal. 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