31. Southern California sits on blind thrust faults , experts say. 32. It is " the poster child of blind thrust faults underneath Los Angeles, " he said. 33. Blind thrust faults produce quakes when one side pushes upward but does not break the surface. 34. Thrust faults typically form ramps, flats and fault-bend ( hanging wall and foot wall ) folds.35. The western margin area is bound by synclines and reverse thrusts faults and is structurally complex. 36. The PTZ also displays blind thrust faults and folds ( essentially buried folds and faults ). 37. Thrust faults are especially scary because many are unseen, concealed beneath mountains of dirt and rock.38. The 24-mile blind thrust fault , which runs from Huntington Beach to Dana Point, was discovered in March. 39. The fault zone contains older ( Tertiary ) mylonites, showing it was a ductile compressive thrust fault . 40. The Palaeozoic basement is traversed by thrust faults more or less parallel to the north-south structural grain.
