| You are in: Science/Nature | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Saturday, 9 November, 2002, 13:56 GMT Geologists dissect massive quake ![]() The USGS scientists have surveyed the length of the fault The biggest earthquake in the world this year produced a scar on the landscape more than 230 kilometres (145 miles) long. Sunday's magnitude 7.9 quake in central Alaska left cracks in the ground that run the length of the Denali fault system but caused minimal damage to property and, amazingly, few injuries and no deaths. The famous Trans-Alaskan oil pipeline also appeared to stand up very well to the shaking - just as its designers and engineers had predicted.
Denali is a so-called strike-slip system, which means the two blocks of rock on either side of the fault grind horizontally past each other. In this case, the northern side moved from the west to the east. A maximum shift of nearly seven metres (22 feet) occurred across the Tok Highway, a road that goes from Tok to Glenallen and intersects with the Alaska Highway. Scientists now say that the main shock started at the western end of the rupture zone and then travelled eastward along the fault, where most of the seismic energy was released. All the data gathered on the quake will help improve models of how faults slip during earthquakes, and give researchers a better understanding of the earthquake hazards associated with large faults. ![]() The scar is traced from a helicopter through the trees ![]() The quake triggered huge rockslides and avalanches ![]() There was some damage to the pipeline at this location ![]() The Richardson Highway was offset here by 2.5 metres | See also: 04 Nov 02 | Science/Nature 19 Jul 02 | Science/Nature Internet links: The BBC is not responsible for the content of external internet sites Top Science/Nature stories now: Links to more Science/Nature stories are at the foot of the page. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Links to more Science/Nature stories |
![]() | ||
| ---------------------------------------------------------------------------------- To BBC Sport>> | To BBC Weather>> | To BBC World Service>> ---------------------------------------------------------------------------------- © MMIII | News Sources | Privacy |