Ghost Forest in Girdwood

The history of earthquakes and tsunamis in Upper Cook Inlet is written in mud and dead trees.

Driving the scenic Seward Highway from Anchorage to Girdwood, at about mile 90, pale columns of dead trees catch the eye. Stripped of bark, with only the remnants of thick branches still extending, the “Ghost Forest” is a memento of the great 1964 9.2 magnitude Alaska earthquake.

The native forest grew in the freshwater region above the ocean range. When the ground dropped about 6.5 feet during the earthquake, it was suddenly below high tide level. Saltwater from the Turnagain Arm of Cook Inlet relentlessly flooded the area at each high tide, killing trees (Figure 1). It still stands in place, now a silent reminder of the place where the 1964 earthquake changed the landscape. Marine sediments slowly bury the evidence.

The ghost forest that can be seen from the highway is not alone. Dig a little deeper, and the broken trunks of two former ghost forests will be revealed (Figure 2). But ghost trees are not the only evidence of disturbances caused by major earthquakes. In the early 2000s, scientists drilled into tidal mud around Girdwood and Anchorage, using a combination of geology and paleontology to decipher past large earthquakes.

The 1964 earthquake caused the ground here to sink several feet compared to sea level. Over several years, silt from the tides buried ghost tree trunks, grasses and marsh plants, creating a layer of peat. “In the peat layers, you can look at fragile leaves and plant material that are still in their growing positions, which indicates that subsidence occurred quickly,” said Barrett Salisbury, earthquake and tsunami hazard program manager for the Alaska Department of Geology and Hazards. Geophysical surveys. “You can also look at tree rings, which show that the tree died quickly. There are no rings that show that the tree was lost over a long period.”

Similar layers of dead bog vegetation (peat and logs) buried deeper in tidal sediments provide geological evidence that 1964-style earthquakes occurred repeatedly in the distant past (Figure 3). Microfossils in these sediments, like diatoms that lived in intertidal zones, show that transitions from freshwater to saltwater environments occurred suddenly during tectonic events, rather than gradually due to long-term sea level rise.

Geologists can also use unique layers deposited in sedimentary soils — for example, ash from the 1912 eruption of Novarupta/Katmai volcano — and other markers and isotopes to help estimate when earthquakes occur. These ghosts of past earthquakes provide dates from about 900 and about 1,600 years ago for two major tectonic events in the Cook Inlet area.

“Researchers studying similar deposits under several coastal marshes around Cook Inlet have found that major earthquakes that likely caused large-scale tsunamis have occurred in this region at a rate of every several hundred years over the past 5,000 years,” Rod Kombelec said. at least”. Alaska Department of Geological and Geophysical Surveys.

If you ever have the chance to pass through the ghostly forest of Girdwood, beware of the history beneath your feet. Admire the expanse of these pale ghosts of trees, traces of the massive scale of Alaska's tectonic movements. Scary, indeed!

Learn more A new tsunami brochure is available for the Girdwood area, detailing evacuation zones, staging areas and more: Learn about tsunami risks in Anchorage, Chugiak, Eagle River, Eklutna and Girdwood

For tsunami information for other communities, visit our Tsunami Products page.

View the story map A Hidden Wave Appears: Tsunami Hazard in Upper Cook Inlet to learn more about the history of tsunamis and earthquakes in Upper Cook Inlet.

What Are The Main Benefits Of Comparing Car Insurance Quotes Online

LOS ANGELES, CA / ACCESSWIRE / June 24, 2020, / Compare-autoinsurance.Org has launched a new blog post that presents the main benefits of comparing multiple car insurance quotes. For more info and free online quotes, please visit https://compare-autoinsurance.Org/the-advantages-of-comparing-prices-with-car-insurance-quotes-online/ The modern society has numerous technological advantages. One important advantage is the speed at which information is sent and received. With the help of the internet, the shopping habits of many persons have drastically changed. The car insurance industry hasn't remained untouched by these changes. On the internet, drivers can compare insurance prices and find out which sellers have the best offers. View photos The advantages of comparing online car insurance quotes are the following: Online quotes can be obtained from anywhere and at any time. Unlike physical insurance agencies, websites don't have a specific schedule and they are available at any time. Drivers that have busy working schedules, can compare quotes from anywhere and at any time, even at midnight. Multiple choices. Almost all insurance providers, no matter if they are well-known brands or just local insurers, have an online presence. Online quotes will allow policyholders the chance to discover multiple insurance companies and check their prices. Drivers are no longer required to get quotes from just a few known insurance companies. Also, local and regional insurers can provide lower insurance rates for the same services. Accurate insurance estimates. Online quotes can only be accurate if the customers provide accurate and real info about their car models and driving history. Lying about past driving incidents can make the price estimates to be lower, but when dealing with an insurance company lying to them is useless. Usually, insurance companies will do research about a potential customer before granting him coverage. Online quotes can be sorted easily. Although drivers are recommended to not choose a policy just based on its price, drivers can easily sort quotes by insurance price. Using brokerage websites will allow drivers to get quotes from multiple insurers, thus making the comparison faster and easier. For additional info, money-saving tips, and free car insurance quotes, visit https://compare-autoinsurance.Org/ Compare-autoinsurance.Org is an online provider of life, home, health, and auto insurance quotes. This website is unique because it does not simply stick to one kind of insurance provider, but brings the clients the best deals from many different online insurance carriers. In this way, clients have access to offers from multiple carriers all in one place: this website. On this site, customers have access to quotes for insurance plans from various agencies, such as local or nationwide agencies, brand names insurance companies, etc. "Online quotes can easily help drivers obtain better car insurance deals. All they have to do is to complete an online form with accurate and real info, then compare prices", said Russell Rabichev, Marketing Director of Internet Marketing Company. CONTACT: Company Name: Internet Marketing CompanyPerson for contact Name: Gurgu CPhone Number: (818) 359-3898Email: [email protected]: https://compare-autoinsurance.Org/ SOURCE: Compare-autoinsurance.Org View source version on accesswire.Com:https://www.Accesswire.Com/595055/What-Are-The-Main-Benefits-Of-Comparing-Car-Insurance-Quotes-Online View photos