Seismicity patterns along the Ecuadorian subduction zone: new constraints from earthquake location in a 3-D a priori velocity model

摘要: To improve earthquake location, we create a 3-D priori P-wave velocity model (3-DVM) that approximates the large variations of Ecuadorian subduction system. The 3-DVM is constructed from integration geophysical and geological data depend on structural geometry properties crust upper mantle. In addition, specific station selection carried out to compensate for high density Andean Chain. synthetic experiments are then designed evaluate network capacity recover event position using only P arrivals MAXI technique. Three location proposed: (1) noise-free (2) noisy used in 3-DVM, (3) 1-DVM. Synthetic results indicate that, under best conditions (exact arrival set 3-DVM), spatiotemporal configuration can accurately locate 70 per cent events frontal part zone (average azimuthal gap 289° ± 44°). Noisy (up 0.3 s) located 50 earthquakes. Processing within 1-DVM almost never allows accurate hypocentre offshore earthquakes (15 cent), which highlights role zone. For application real data, seismicity distribution 3-D-MAXI catalogue also compared determinations obtained 1-D-layered VM. addition good-quality uncertainties, clustering depth confirm reliability. pattern (a 13 yr record during inter-seismic period seismic cycle) rupture asperity Mw = 7.9 1942 7.7 1958 (the 8.8 1906 patch not defined). We observe nucleation 1942, coincides with areas positive Simple Bouguer anomalies where marine terraces still preserved coastal morphology. From north south: aseismic attributed coupling; south Galera alignment (perpendicular trench), presents moderate seismicity, deeper seismogenic interplate zone, abutting Jama cluster (to south). This facing Cabo Pasado cap overriding margin. suspect this reflects local (partial coupling). South cluster, spherical Bahia area interpreted as having low coupling (steady creep motion or slow slip events). site generated three M > 7 (1896, 1956 1998) correspond small strong coupling. south, Manta-Puerto Lopez mainly organized swarms (1998, 2002, 2005). Although have been observed (Vallee et al. submitted), infer coastline shape, here might reveal significant amount