Earthquakes Are Like “JELL-O”: The Effects of Local Geology, Topography, and Physical Effects in East Coast versus West Coast
Earthquakes can be like something from “JELL-O”. In a simple analogy, sitting in a valley or basin is like sitting in a bowl of jello and it will shake more than the surrounding rock.
“The local geology definitely matters — what you’re sitting on,” said Dr. Susan Hough, a geophysicist with the US Geological Survey. “What the topography is, it definitely matters.”
Earthquakes are broken down into two basic wave types: body waves (often called P-waves or S-waves which travel through the Earth) and surface waves (which travel along the Earth’s surface).
While a P wave is still a P wave, and a S wave is still a S wave, their speeds and amplitudes will change according to the type of rock.
There are three important factors in earthquakes, energy left at the source, amplification by the local geology, and then what happens in between. “It’s the in between that really matters for East Coast versus West Coast.”
When it comes to earthquakes, the size is very important. The magnitude of an earthquake is determined by the physical size. A moderate earthquake and a powerful one are both examples. The scale is logarithmic, so each whole number increase in magnitude represents a tenfold increase. So, a 6.5 magnitude quake is 10 times bigger than a 5.5 magnitude, not one times bigger like the number implies.
A magnitude-7.8 earthquake hit southeastern Turkey and parts of Syria in the early hours of the morning of 6 February. Thousands of people are known to have died and thousands more were injured. The magnitude-7.5 earthquake and more than 200 aftershocks were followed by 9 hours.
The depths and magnitude were also similar. The earthquakes in Haiti and California were both over 10 miles deep. While 8 miles may not sound shallow, it is in terms of earthquakes. Geologically speaking, any earthquake that is less than 43 miles (70 km) deep is considered shallow. The more likely damage will occur if the earthquake is shallow.
An earthquake in Kathmandu, Nepal, that levelled a multistory building after the New Madrid earthquake of 15 April 2015 in the Californian capital
Low frequencies mainly affect multistory buildings in particular. In fact, the lower the frequency, the bigger the buildings that will be affected. Whereas high frequencies tend to affect small buildings.
Constructing on harder ground provides more stability for the buildings because essentially the rock absorbs the waves. There was an earthquake that leveled multistory buildings in the capital of Kathmandu in 2015.
Some people living 100 miles away woke up during the 1906 California earthquake. “Whereas the New Madrid earthquakes (which happened in 1811 and 1812 in present-day Missouri), it actually rang church bells in Charleston, South Carolina. That has to do with how the waves travel through the crust. There is a difference.
More than two dozen smaller quakes – as powerful as a 4.6 magnitude – struck the area afterward, the survey reported. The main quake produced at least some shaking from coastal Oregon to south of San Jose, California, public reports collected by the survey show.
Earthquake-soil-rock-types-xpn: The effects of the lake bed zone on buildings and ships in Port-au-Prince
Haiti also has a topographical aspect to it. Port-au-Prince sits mostly at sea level, with sandy sediments in those low-lying areas. But just 10-15 miles away, the elevation increases several thousand feet into a more mountainous terrain with harder rock at the surface.
The amplification in Kathmandu was due to the lake bed zone, but the valley was not as loud as it could have been. You had one thousand, two thousand and four thousand items, and they all went to one side. The strength of the motion is due to the lake bed. But the effect on buildings depends on the size of the buildings.”
A big swell in the ocean will be damaging if it causes the boat to collide with it. The bow of the ship would go up while the stern went down in a big swell. The whole ship just goes up and down if it is smaller than the swell.
Ground failure is a major contributor to earthquake damage.
“It takes time for first responders and experts to survey the actual damage in the area, so our product provides early estimates of where to focus attention and response planning,” according to the USGS.
The models do not predict very specific occurrences because they don’t show initial awareness or extent.
The 2010 quake in Humboldt County, Puerto Rico, caused more than 23,000 slides to form and result in power outage
The strong shaking that occurred across the island of Hispaniola in 2010 caused more than 23,000 slides to form.
“There is something called non-linearity, and it turns out that if you try to shake soft sediments really hard, it’s not a bowl of Jell-O as much as it is a sandbox,” Hough says.
For example, Hough explains that if you shake a sandbox really hard, it’s going to stop acting like rock. Things are going to shift around at grain-size level and that process absorbs energy.
The sand in India may behave like a liquid if it is water saturated. Liquefaction has a couple of consequences for shaking: some of the potentially damaging shaking gets absorbed, which can be a good thing, but if the ground beneath a structure starts behaving like a liquid, the structure no longer has a solid foundation. It’s like it’s sitting on quicksand. Even a well-built building can just tip over,” Hough told CNN.
The quake, striking at 2:34 a.m. PT, was centered in the Pacific just off the coast, about 7.5 miles from the Humboldt County city of Ferndale, the survey said. It is a 20-mile drive southwest of Eureka and a 280-mile drive northwest ofSacramento.
Most homes and businesses in Humboldt County were without power early Tuesday. There were 71,000 Outages reported by 4:30 a.m. Power Outage.us tracks 99,000 customers in the county.
The Twin Cities of a Los Alamos-Bondi-Californio, California, Earthquake. On December 20, 2021
We got our phones after the shaking stopped and looked around. Everything was in shambles.” The Monolias said that. “Things you wouldn’t expect to have fallen over or broken did. The cabinet in the bathroom fell apart.
In a video she posted on social media, a number of items spilled onto the floor in her home. This was a large one. The power is out. House is a big mess,” Titus wrote.
The temblor left cracks in a bridge in Ferndale and debris on its roadway, the California Highway Patrol said. Police closed the span, CNN affiliate KRCR reported.
A 6.0 magnitude earthquake struck the area a year ago. That quake struck just off Humboldt County’s Cape Mendocino on December 20, 2021, and caused minor damage to buildings in the area.
Seyhun Puskulcu: A father and son of a boy killed in Istanbul after the September 17 terrorist attack, and why Sedat is alive
Turkey’s government said search and rescue teams have pulled more than 8,000 people from underneath the rubble of thousands of toppled buildings in the past two days. There were concerns that survivors may succumb to their injuries due to the worsening weather conditions.
More than 20,000 people have died as a result of the earthquake that hit Turkey and Syria on Monday. Emergency crews are still looking for survivors but demolition work is happening in some areas.
The Turkish Earthquake Foundation is based in Istanbul, and its convener, Seyhun Puskulcu, says people are aware of their vulnerability to earthquakes. “This wasn’t a surprise,” says Puskulcu, who last week was touring the cities of Adana, Tarsus and Mersin, and areas of western Turkey, delivering workshops on earthquake awareness.
I believe my son is still alive after all these years. She toldNPR that his brother dug to find him. Hours later, as diggers chipped away at the ruins of the building, rescuers found Sedat’s body and wrapped it in a blanket for his mother to say goodbye.
Earthquake aftershocks, and the rebuilding of Turkey, says David Rothery, a geoscientist at University College London
Disaster rescue groups consider the first 72 hours after a disaster to be crucial. In neighboring Syria, the government has blamed Western sanctions for hampering relief efforts, but the U.S. says sanctions do not include humanitarian assistance. Regardless, northern Syria lacks the heavy equipment and other infrastructure to come to the aid of the hundreds of thousands displaced by this disaster, and the only U.N.-authorized road from Turkey to that region has been damaged by the quake.
Iran, Libya, and the United Arab Emirates have sent hundreds of millions of dollars worth of aid to Syria, and dozens of countries have sent aid to Turkey, including more than 5,000 rescue workers who are arriving in the disaster area.
More than 360,000 people have been temporarily displaced by this disaster, and Turkey has set up more than 70,000 tents for them to live in.
People need to be prepared for more earthquakes and other weather related problems, says researchers. “The possibility for major aftershocks causing even more damage will continue for weeks and months,” says Ilan Kelman, who studies disasters and health at University College London.
Most of Turkey sits on the Anatolian plate between two major faults: the North Anatolian Fault and the East Anatolian Fault. The tectonic plate that carries Arabia, including Syria, is moving northwards and colliding with the southern rim of Eurasia, which is squeezing Turkey out towards the west, says David Rothery, a geoscientist at the Open University in Milton Keynes, UK. He says Turkey is moving west about 2 centimetres a year. “Half the length of this fault is lit up now with earthquakes.”
In 1999, a magnitude-7.4 earthquake hit 11 kilometres southeast of Izmit, Turkey, killing more than 17,000 people and leaving more than 250,000 homeless. The Turkish government made a compulsory earthquake insurance system mandatory after this tragedy. A civil engineer at Boazii University says that many of the buildings that were damaged in this week’s earthquake were built before 2000.
According to a study published last March in soil Dynamics and Earthquake Engineering, the center of the city of Gaziantep would be damaged by a magnitude-6.5 earthquake. This is because most existing buildings are low-rise brick structures that are constructed very close to each other.
Things are worse in Syria, where more than 11 years of conflict have made building standards impossible to enforce. Buildings collapsed in Syria’s northern regions after the earthquake. Some war-damaged buildings in Syria have been rebuilt using low-quality materials or “whatever materials are available”, says Rothery. “They might have fallen down more readily than things that were built at somewhat greater expense. We’ve yet to find out,” he adds.
The weather forecast for the region tonight is currently below freezing. Those who are trapped in the rubble, who might be rescued, could freeze to death. These hazard continue, he says.