Earthquakes have made recent news in the United States with large earthquakes happening in Alaska. So, this week, we’re shaking things up this week and talking with Dr. Shawn Wei and Dr. Jeffery Freymueller about earthquakes. We wanted to know what they are, what causes them, what the consequences of an earthquake are, what does the Richter scale even mean?
“Earthquakes are caused by forces acting within the earth that either breaking rock or taking rock where there is already a fracture and making that move- forcing motion on that fracture.”
“[In the deep earth it isn’t] brittle materials, but more like silly putty. And in those cases, you don’t expect any break in silly putty. That’s why, for many years, we don’t understand why there are earthquakes at much greater depth.”
“There are earthquakes happening all over the world, all the time.”
“A seismometer is an instrument that tries to measure all the ground motion- the ground shaking…and then we could even measure the ground shaking in New Zealand!”
“In 2011 with the earthquake in Japan, there were some places on the coast of Japan that moved as much as 15 feet seaward.”
“The Richter scale…this word is very old fashioned…and he developed a scale [specific for Southern California] so right now we have better technology and can detect earthquakes further away and have different scales and we use another scale- moment magnitude.”
“We are using a special scale called a log scale*, so the magnitude or energy increases dramatically with an increase in numbers.” *Find out more about log scales here.
“We can do long term forecasts that are important for hazards…and the longer the time, the better we can make an assessment.”
“There’s a lot of work that’s put into contracting probabilistic forecasts over time of, like, 100 years or 50 years, and that’s helpful in particular for structures…Those [structures] tend to have a long life span and so having a really good assessment of what is likely over a long time is really useful.”