@article{fdi:010092619,
  title = {{E}arthquake detectability and depth resolution with dense arrays in {L}ong {B}each, {C}alifornia : further evidence for upper-mantle seismicity within a continental setting},
  author = {{I}nbal, {A}. and {A}mpuero, {J}ean-{P}aul and {C}layton, {R}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he {N}ewport-{I}nglewood fault ({NIF}) is a slowly deforming fault cutting through a thin continental crust with a normal geothermal; yet it hosts some of the deepest earthquakes in southern {C}alifornia. {T}he nucleation of deep earthquakes in such a continental setting is not well understood. {M}oreover, the deep seismogenic zone implies that the maximum {NIF} earthquake magnitude may be larger than expected. {H}ere, we quantify the resolution of the {L}ong {B}each ({LB}) and the {E}xtended {L}ong {B}each ({ELB}) dense arrays used to study deep {NIF} seismicity. {P}revious study of the regional catalog and of downward-continued {LB} array data found {NIF} seismicity extending into the upper mantle beneath {LB}. {L}ater studies, which analyzed the {ELB} raw data, found little evidence for such deep events. {T}o resolve this inconsistency, we quantify the array's microearthquake detectability and resolution power via analysis of pre- and postdownward migrated {LB} seismograms and benchmark tests. {D}ownward migration focuses energy onto the source region and deamplifies the surface noise, thus significantly improving detectability and resolution. {T}he detectability is also improved with the increase in the array aperture-to-source-depth ratio. {T}he {LB} array maximum aperture is only 20% larger than the {ELB} aperture, yet its resolution for deep (>20 km) events is improved by about a factor of two, suggesting that small changes to the array geometry may yield significant improvement to the resolution power. {A}ssuming a constant aperture, we find the {LB} array maintain resolution with 1% of its sensors used for backprojection. {H}owever, the high-sensor density is essential for improving the signal-to-noise ratio. {A}nalysis of the regional and array-derived {NIF} catalogs together with newly acquired {M}oho depths beneath the {NIF} suggests that mantle seismicity beneath {LB} may be a long-lived feature of this fault.},
  keywords = {{ETATS} {UNIS} ; {CALIFORNIE}},
  booktitle = {},
  journal = {{S}eismological {R}esearch {L}etters},
  volume = {96},
  numero = {1},
  pages = {157--167},
  ISSN = {0895-0695},
  year = {2025},
  DOI = {10.1785/0220240035},
  URL = {https://www.documentation.ird.fr/hor/fdi:010092619},
}