A new study warns Southern California's faults are more stressed than at any point in 1,000 years — bad news for the greater Los Angeles area.

• A spot northeast of LA called Cajon Pass is where the San Andreas and San Jacinto faults nearly meet, and it could let a quake jump across both at once.
• A quake rupturing both faults together would be far worse than one fault alone, threatening LA, San Bernardino, Riverside, and key highways, rail, water, and power lines.
• Stress on these faults is at record highs and lining up the way it has before past giant quakes.
• No one can predict the day, but the system is described as critically stressed right now.
• Doubts about California's emergency readiness loom large after the recent wildfire response.

Outlook: A "big one" can't be timed, but the data suggests the region is primed for a major quake, and preparation is urged now.