Beneath the bustling neighborhoods of Los Angeles is a somewhat underrated threat: a network of faults that present perhaps a bigger earthquake risk than the notorious San Andreas fault.

Not because the San Andreas isn't ready to shake — it is —but because the Puente Hills thrust fault system sits right under densely-packed residential neighborhoods in northeast LA and surrounding cities like Pasadena.

Is LA ready for a quake that could level some non-retrofitted buildings? Scripps News spoke to experts and went behind the scenes at one of the world's leading facilities for testing buildings' earthquake resilience.

For the full report, click on the video player above.