Turnagain Heights Slide from the "Good Friday" Earthquake, 1964 - Anchorage, AK
Posted by: Groundspeak Premium Member NorStar
N 61° 11.910 W 149° 58.817
6V E 339854 N 6788548
Quick Description: A cluster of interpretive signs and paved trails allow you to understand how the uneven and terraced landforms came to be from the "Good Friday" earthquake that hit Alaska on March 27, 1964.
Location: Alaska, United States
Date Posted: 10/17/2010 6:47:12 AM
Waymark Code: WM9YGM
Published By: Groundspeak Premium Member RakeInTheCache
Views: 10

Long Description:
In Anchorage, on Pt. Wolonzof, is Earthquake Park, a wooded park that has interpretive signs that explain the great natural disaster of the "Good Friday" Earthquake that struck on March 27, 1964, and interpret the terraced land features between the bluff and the Knik Arm nearby that were the result of the the earthquake.

The Earthquake

The web site for the Alaska Earthquake Information Center has a detailed page concerning the earthquake. The opening paragraph states:

On March 27, 1964, at 5:36 p.m. ADT (03:36 3/28 UTC) a great earthquake of magnitude 9.2 (moment magnitude) occurred in Prince William Sound region of Alaska. The epicenter was about 10 km east of the mouth of College Fiord, approximately 90 km west of Valdez and 120 km east of Anchorage. The epicenter was located at Lat. 61.04N, Lon. 147.73W, at a depth of approximately 25 km. This earthquake is the second largest earthquake ever recorded in the world. after a M9.5 earthquake in Chile in 1960. The duration of rupture lasted approximately 4 minutes (240 seconds).

The web site continues to explain the cause of the quake:

The northwestward motion of the Pacific plate at about 5 to 7 cm per year causes the crust of southern Alaska to be compressed and warped, with some areas along the coast being depressed and other areas inland being uplifted. After periods of tens to hundreds of years, this compression is relieved by the sudden southeastward motion of portions of coastal Alaska as they move back over the subducting Pacific plate.

It goes on to explain that the movement of Alaska land over the Pacific Plate in the Prince William Sound moved 9 m (about 30 ft) on average, and as much as 18 m (60 ft).

The earthquake could be felt literally all over the world, as the earth "rang like a bell," and seismic waves propagated to locations like Texas and Florida. Significant damage due to the earthquake itself was seen all over Alaska, and into Canada and Washington state. Tsunamis also were formed and destroyed property and caused loss of human lives as far south as Oregon and California.

The epicenter was about 80 miles east of Anchorage, but Anchorage was badly damaged. Many downtown and coastal buildings were destroyed and the land made significant shifts.

Earthquake park was established here to highlight the features of the bluff that shifted during the earthquake. One of the interpretive signs has a land cross section showing the present bluff with faults where pieces of the bluff slipped, and a dashed red line showing the original height of the bluff facing Knik Arm. The sign explains that there is a layer of bluish clay called Bootlegger Cove Clay. The clay is a fine, silty material that 'liquefied' during the earthquake, thus losing all strength in supporting the surface layer and causing a strip of the bluff, 8,000 ft long and 1,200 ft wide, to collapse. When it collapsed, about 75 homes were 4 lives were lost.

Today, the evidence is less visible, since the trees have grown back, as well as ground plants. Yet, when you peer into the woods, to the right of the memorial, you can see strong evidence of sunken and terraced sections, leading down to the Arm. There aren't a lot of paths through the terraced area, but the Tony Knowles Coastal Trail does go it - take a right at the intersection when coming from the parking lot. There are also signs posted that warn you against walking on the mud flats as you can easily get stuck, and there is a danger of drowning.

To get to the park, park at a parking lot for the Tony Knowles Coastal Trail on Northern Lights Blvd/Point Woronzof Rd (depending on the map you may be using). There is a short walk of about a quarter mile on flat, paved road to an intersection with curved I-Beams forming arches. Two are smoothly curved, while two on the other side are wavy to show mark the pathway to the memorial, and possibly the line where the bluff slipping began. The path to the monument is about 100 ft from the intersection. The monument is concrete and has the appearance of an unevenly stepped staircase. At this location, there is also a viewing area of the Cook Inlet as well as historical signs.

The location is really not accessible by public transportation. The nearest buses are Route 7A (stops at the Anchorage International Airport) and Route 36 (stops on Northern Lights Blvd), but then you would have to walk almost a mile to get to the parking lot. Other than car, you could take a long walk or a bike to the location along the Tony Knowles Coastal Trail. From downtown Anchorage it is about 4 miles to the park.

Other Information:

Anchorage.net (Good Friday Earthquake): Visit Site
Waymark is confirmed to be publicly accessible: yes

Parking Coordinates: N 61° 11.775 W 144° 58.654

Access fee (In local currency): .00

Requires a high clearance vehicle to visit.: no

Requires 4x4 vehicle to visit.: no

Public Transport available: no

Website reference: [Web Link]

Visit Instructions:
No specific requirements, just have fun visiting the waymark.
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