2000 Yountville earthquake facts for kids
| UTC time | 2000-09-03 08:36:30 |
|---|---|
| ISC event | 1739620 |
| USGS-ANSS | ComCat |
| Local date | September 3, 2000 |
| Local time | 01:36 PDT |
| Magnitude | 5.0 Mw |
| Depth | 9.4 kilometers (6 mi) |
| Epicenter | 38°23′N 122°25′W / 38.38°N 122.41°W |
| Type | Strike-slip |
| Areas affected | North Bay (San Francisco Bay Area) California, United States |
| Total damage | $10–50 million |
| Max. intensity | VII (Very strong) |
| Peak acceleration | 0.50 g |
| Casualties | 41 injured |
The 2000 Yountville earthquake was a moderate earthquake that happened near Yountville, California. It struck on September 3, 2000, at 1:36 AM Pacific Daylight Time. The earthquake had a strength of 5.0 on the moment magnitude scale. It was caused by a fault that scientists didn't know about before. The earthquake's center was about 3 miles (4.8 km) southwest of Yountville, in the Mayacamas Mountains under Mount Veeder.
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What Caused the Yountville Earthquake?
The earthquake happened about 9.4 kilometers (5.8 miles) deep underground. It was caused by a type of fault called a strike-slip fault. This means the ground on either side of the fault moved past each other sideways. The fault was pointed northwest. The exact spot where the earthquake started, called the epicenter, was close to the West Napa Fault. This was a fault that had not been mapped before.
How Did the Yountville Earthquake Affect People and Buildings?
Damage to Buildings
Many old buildings in downtown Napa were damaged. These buildings were made of brick or stone without extra support, so they were not very strong. After the earthquake, 16 buildings were marked with a "red tag." This meant they were too unsafe to enter. Another 168 buildings got a "yellow tag," meaning they had some damage but might be safe after repairs.
Why Was the Shaking So Strong?
Even though the earthquake was not super powerful (magnitude 5.0), the shaking felt very strong in Napa. This is because Napa is built on soft, sedimentary soil. Soft ground can make earthquake shaking feel much stronger than it would on solid rock.
Other Effects of the Earthquake
About 10,000 homes lost electricity because of the earthquake. Many houses had chimneys that cracked or fell over. Some homes also had broken water pipes because their water heaters tipped over. Luckily, roads, bridges, and other transportation systems in the area were not badly damaged. In total, 41 people were injured, but no one died.
