[뉴스퀘어10] '불의 고리' 아닌 베네수엘라에 연쇄 강진...원인은? / YTN

■ Hosts: Anchor Park Seok-won, Anchor Jo Ye-jin ■ Guest: Kim Kwang-hee, Professor, Department of Geological and Environmental Sciences, Pusan ​​National University The text below may differ from the actual broadcast content. Please refer to the broadcast for more accurate information. When citing, please specify [YTN News Square 10AM]. [Anchor] Now, we will connect with an expert to examine this in more detail. We are connected with Professor Kim Kwang-hee from the Department of Geological and Environmental Sciences at Pusan ​​National University. Professor, are you there? [Kim Kwang-hee] This is Kim Kwang-hee from Pusan ​​National University. [Anchor] This earthquake is being called a so-called "twin earthquake" because strong tremors exceeding magnitude 7 occurred more than twice. Is this an exceptional case? [Kim Kwang-hee] First of all, this is not a common occurrence. Generally, small aftershocks follow a large earthquake, but as seen in yesterday's earthquake, two large earthquakes of similar magnitude—magnitude 7.2 and magnitude 7.5—occurred on the same fault line within a very short time interval. So, since this is a rare occurrence, we also refer to it as a doublelift earthquake or a twin-sequence earthquake. [Anchor] I heard that the energy of this earthquake is equivalent to the explosive power of 240 Hiroshima atomic bombs. It’s hard to grasp the reality of it. What is the magnitude of this? [Kim Gwang-hee] Actually, we do use expressions like "a massive earthquake equivalent to several atomic bombs," but this isn't a term generally used in the scientific community. You can think of it as a metaphor used to help the general public understand it more easily. Generally speaking, a magnitude 7.5 earthquake is equivalent to about 2.5 megatons of TNT, and a magnitude 7.2 earthquake is about 1 megaton. So, when combined, it amounts to 3.6 megatons. Considering that the Hiroshima atomic bomb was about 15 kilotons, people say this is roughly equivalent to about 240 bombs. However, in the case of the Hiroshima bomb, the energy was released from a single point, whereas this earthquake occurred over a considerably wide area rather than being released from a single spot. Since it was energy accumulated over a large area known as a fault plane that was released, it is not easy to directly compare it to the energy release from the Hiroshima nuclear power plant. [Anchor] It is said that the damage was exacerbated this time because the epicenter was relatively shallow and the ground consisted of alluvial soil. What is the cause of this? [Kim Gwang-hee] Generally, earthquakes occur at considerable depths. Therefore, if an earthquake occurs at a depth of 20 km, the distance to the surface is still about 20 km, so energy tends to weaken during the transmission process. However, since the depth is only 10 km, the energy reaches the surface where people live without being sufficiently weakened, which means it can shake more strongly. Also, in the case of this earthquake, a phenomenon called ground amplification can occur depending on where buildings are located. You can think of it as a phenomenon where energy is strengthened or the shaking intensifies. These amplification phenomena usually occur more frequently in soft ground rather than in hard ground in mountainous areas. When shaking occurs in such places, a phenomenon called liquefaction—which is a landslide—can occur along with the seismic shaking. I believe that the extent of damage can also vary depending on how the buildings are constructed. [Anchor] Let's take a look at the damage situation. To date, the officially confirmed death toll alone stands at 188, with over 1,500 injured. This figure is likely being continuously updated on-site. Going forward, how far can we estimate the specific scale of the damage... (Excerpt) YTN Lee Kang-moon ([email protected]) ▶ Original Article : https://www.ytn.co.kr/_ln/0104_202606... ▶ Report a Tip : https://mj.ytn.co.kr/mj/mj_write.php ▣ Subscribe to YTN YouTube Channel : http://goo.gl/Ytb5SZ ⓒ YTN Unauthorized reproduction, redistribution, and use of AI data are prohibited