COLLABORATIVE RESEARCH: Continuation of a GPS-Based Study of Slip Along The Rivera Subduction Interface Following the October 9, 1995 Mw=8.0 Jalisco Earthquake

我们建议继续使用墨西哥西部现有的24个站点GPS网络对Rivera和cocos北部俯冲带进行基于GPS的研究。我们的具体目标是区分地震后运动的深度弹性滑动和深度粘性流动模型的预测，确定地震后滑动是否在地震发生后几年内衰减，并立即恢复稳定的地震间应变积累，评估地震间应变积累是否集中在俯冲界面中最能适应同震滑动的部分。为了确定同震破裂的障碍（例如速度增强区域）是否对应于明显的余震区域，因为可能沿俯冲断层的预期摩擦遵循速率和状态变量的本构律，并确定地震间应变是否与完全锁定的断层一致，正如预期板滑与同震释放滑动的比较所表明的那样。为了实现这些目标，我们将继续每年和连续占领网络，并加强地震后位移的建模。

We propose to continue a GPS-based study of the Rivera and northernCocos subduction zones using an existing 24 site GPS network in westernMexico. Our specific goals are to discriminate between the predictionsof elastic-slip-at-depth and viscous-flow-at-depth models forpostseismic motion, to determine whether postseismic slip decays within afew years of the earthquake and is immediately followed by a resumptionof steady interseismic strain accumulation, to assess whether interseismicstrain accumulation is focused along parts of the subduction interfacethat accommodated the most coseismic slip, to determine whetherbarriers to the coseismic rupture (e.g. velocity-strengthening regions)correspond to regions of significant afterslip, as might be expected iffriction along the subduction fault obeys rate- and state-variableconstitutive laws, and to determine whether interseismic strainis consistent with a fully-locked fault, as comparisons of expected plateslip versus coseismically-released slip suggest. Toward these goals,we will continue annual and continuous occupations of the network,and intensive modeling of postseismic displacements.