A magnitude 7.4 quake lands in the "major" category per USGS standards. Its impact varies by location, but the mechanics are consistent.
**Ground shaking:** Intensity hits MMI VIII–IX near the epicenter. This is severe to violent. Peak ground acceleration registers strongly tens to a couple hundred kilometers away. Damage concentrates within 50–100 km of the rupture. Depth and directivity shift these numbers slightly.
**Structural damage:** Code-compliant buildings—reinforced concrete, engineered steel, retrofitted structures—usually survive. They show cracks. Non-structural elements may fall. They stay standing. Unreinforced masonry and adobe do not fare as well. Partial or total collapse is common there. Infrastructure suffers too. Landslides, liquefaction, and ruptured roads appear. Bridges break. Power, water, and communications go down.
**Casualties:** You cannot predict deaths from magnitude alone. Local building codes, population density, time of day, and depth matter more. Historical M7.4 events show this range. Some killed a handful of people in engineered regions. Others killed thousands in dense, poorly constructed areas. There is no single typical casualty figure. Magnitude is a weak predictor of death toll.
**Geographic extent:** Severe shaking stays within roughly 50–100 km of the rupture. The tremor itself travels further. People feel it hundreds of kilometers away without damage. Secondary effects expand the footprint. Tsunamis, if offshore, or regional landslides reach farther.
**Bottom line:** M7.4 is major and regionally destructive. It causes severe damage and significant casualties. Local factors dominate the outcome. Construction quality, depth, and population exposure matter more than the number 7.4. "Typical" implies a wide range, not a fixed value.
This is factual information. No code, deliverables, repos, or write actions are involved. Standards-lens routing, durability classing, outbox, and handoff-schema governance do not apply. There is nothing to land, mirror, or hand off.
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