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On November 30th, 2018, a magnitude 7.0 earthquake struck the area near Anchorage, Alaska. The earthquake hit more precisely, 8 miles north of the city, but the tremors could be felt up to 400 miles away.
On top of the original earthquake, more than 1,000 aftershocks have hit the area since Friday. The majority of the follow-up quakes have been under a magnitude 2.5, which means that the Anchorage community likely did not feel most of them. However, up until Sunday evening, there were occasional aftershocks that hit 5.0 on the Richter scale.
While Anchorage may be Alaska’s largest city, home to about 40% of the state populace, the most northern city (100,000+ citizens) in the United States only has a population of 300,000. Because of its small size and the frequency with which earthquakes hit America’s Last Frontier, Anchorage is one of the most well-prepared cities in the world for disasters like these. This preparedness has prevented any loss of life since the quake hit on Friday.
However, with an earthquake of this size, some damage is unavoidable. Most of the destruction has come in the form of structural damage to homes and buildings. The most shocking damage, however, has been seen on roadways that have seemingly buckled from within. The aerial photos of these highways have become the most recognizable face of Friday’s destructive natural phenomenon.
Many places where the ground appeared ripped in half, causing roadways to split or sink, are said by meteorologists to have experienced “slope failure”. Slope failure refers to when a solid hill caves in or tears. Essentially, it is a landslide that happens on solid ground.
For local Alaskans living in and around Anchorage, the effects are mostly being felt through the water supply and power. Many people in Anchorage are reporting that their usually high-quality water supply is coming out of the tap with a reddish-brown hue. Crews are addressing ruptured water lines and are advising people to boil their water prior to drinking it in the meantime. As for power, there are some still without it — problematic as Anchorage approaches the heart of its dark, frigid winter season. Shelters have been opened across the city for anyone needing a warm place to sleep, although updated reports continually show that power has been increasingly restored across the city.
Since original damage was reported, the US has declared a health emergency, allowing for the flow of federal aid to continue easily. Alaskan officials have also comforted concerns of supplies entering the state, as normal shipments of food and other necessities from the lower 48 have continued without trouble.
Preliminary estimates place the economic blow somewhere between $150 million-$1 billion.
7.0 earthquakes are huge. To give an idea of how the Richter scale works, a 7.0 earthquake is 10 times bigger than a 6.0 but in terms of energy released, is 32 times stronger. And in comparison to a 5.0 earthquake, a 7.0 is 100 times bigger and 1,000 times stronger.
Mass destruction and a high death toll are not unprecedented for a 7.0 earthquake. Many people remember the 2010 Haiti earthquake. This tremor was also registered as a 7.0, but in Haiti somewhere between 160,000 and 320,000 people died. Aside from the Anchorage’s earthquake-ready infrastructure, seismologists and meteorologists agree that more damage did not occur because the Anchorage quake happened at a lower depth.
Earthquakes in Alaska
California often gets all the earthquake attention, but this is largely based on population as Alaska has significantly more quakes per year. Alaska’s main fault line slips on average two inches per year, about twice the amount of slip rate that the dreaded San Andreas Fault experiences in California.
Every year Alaska experiences an average of 40,000 earthquakes. While many of these are minor or occur in remote parts of the state, Alaska is constantly at risk of dangerous tremors. Alaska also experienced a 9.2 earthquake in 1964, the second largest ever recorded, which nearly leveled Anchorage.