알래스카 규모 7.0 강진…앵커리지 재난지역 선포 VIDEO: Alaska earthquake: Here's what the destruction looks like from the scene

Alaska earthquake: Here's what the destruction looks like from the scene

Joel Shannon, USA TODAY Published 4:38 p.m. ET Nov. 30, 2018

Why a powerful Alaska earthquake cracked roads but should cause few fatalities

The magnitude 7 temblor struck near Anchorage, but the state is no stranger to geologic hazards.

BY MAYA WEI-HAAS

PUBLISHED NOVEMBER 30, 2018

Earthquakes are unpredictable and can strike with enough force to bring buildings down. Find out what causes  earthquakes, why they're so deadly, and what's being done to help buildings sustain their hits. 

알래스카 규모 7.0 강진…앵커리지 재난지역 선포 도심 건물 균열…도로·철도 폐쇄 쓰나미 경보 발령 후 해제…인명피해 보고되지 않아    미국 알래스카 앵커리지 부근에서 30일 규모 7.0의 강진이 발생해 도로와 철도가 폐쇄되고 건물들에 균열이 발생했다고 AP통신, CNN 등이 보도했다.  미지질조사국(USGS)에 따르면 지진은 이날 오전 8시29분 앵커리지에서 북쪽으로 12㎞ 떨어진 곳에서 일어났다. USGS는 이번 지진의 깊이는 40.9㎞로 측정됐다고 발표했다.  아직까지 지진으로 인한 인명피해는 보고되지 않았다. 지진 직후 알래스카 해안 지역에 쓰나미(지진해일) 경보가 발령됐지만 곧 해제됐다. 쓰나미 경보가 해제된 이후에도 여진은 이어졌다.   본진에 이어 규모 5.7의 여진이 감지되기도 했다.  빌 워커 알래스카 주지사는 앵커리지 일대를 재난지역으로 선포했다. 지진으로 앵커리지 건물, 가로등과 나무들이 크게 흔들렸으며 진동에 놀란 시민들이 밖으로 뛰쳐나왔으며 일부 시민들은 책상 등에 몸을 숨겼다. 앵커리지 인구는 약 30만명이다.  에단 버코위츠 앵커리지 시장은 "지진이 발생했을 당시 큰 흔들림이 감지됐다"며 "우리는 지진이 자주 발생하는 지역에서 살고 있지만 이번 흔들림은 매우 크게 느껴졌다"라고 말했다.  Deadline edited by kcontents 이번 지진으로 알래스카 공항에서 모든 항공기의 이착륙이 한동안 금지됐다. 지진의 영향으로 관제탑의 전화선이 끊겼으며 직원들은 안전을 이유로 건물 밖으로 대피했다. 백악관은 G20 정상회의 참석차 아르헨티나 부에노스아이레스를 방문한 도널드 트럼프 미국 대통령이 이번 지진에 대해 보고를 받았다고 밝혔다.  트럼프 대통령은 30일 자신의 트위터에 "위대한 알래스카 주민들이여. 당신들은 '큰 지진'으로 피해를 입었다. 당신들을 돕기 위해 그곳에 복무하는 안전 요원들의 지시를 잘 따르기 바란다. 연방정부는 비용을 아까지 않을 것이다. 신의 가호가 있기를 바란다"고 전했다.  알래스카는 '불의 고리'라고 불리는 환태평양 조산대에 위치해, 연간 4만 차례의 크고 작은 지진이 일어난다.  지난 1964년 3월27일 미국 역사상 최대 규모인 규모 9.2의 대지진이 앵커리지 동쪽 120㎞ 지점에서 일어나 약 130명이 목숨을 잃었다.  <뉴시스>

edited by kcontents

Just before 8:30 a.m. local time on November 30, a magnitude 7 earthquake rattled southern Alaska. The waves rumbled from an epicenter just eight miles north of Anchorage, the state's most populated city—downing power lines, collapsing roads, and sending people fleeing for cover. A tsunami warning was issued soon after the shaking started, but it was lifted by 10:00 a.m. local time.

The quake was “certainly a pretty big one,” says Ben Andrews, the director of the Smithsonian's Global Volcanism Program. So far, reports suggest that the earthquake and its aftershocks were tough on the region's infrastructure, but very few fatalities are expected, in part because Alaska is prepared for such an event.

SFGate

edited by kcontents

The region is the most earthquake-prone in the United States, with an average of one magnitude 7 to 8 temblor striking each year since 1990. In 1964, a magnitude 9.2 earthquake that shook the region became the largest yet recorded in the United States. The intense shaking and subsequent tsunamis killed 131 people.

As reports of the aftermath from this latest earthquake roll in, you might have some questions: Why did it happen? How bad will the damage get? And how does Alaska prepare for such disasters? We've got you covered.

Why are earthquakes common in Alaska?

Nestled off Alaska's southern shoreline, the Aleutian Trench is a deep oceanic groove that is the result of colliding tectonic plates—the ever-shifting slabs of rock that make up Earth's surface. The Aleutian Trench forms where the northern edge of the Pacific plate plunges deep underneath the North American plate.

The plates don't move fast: they shift at roughly the speed at which your fingernails grow, or just a few centimeters a year, Andrews says. But they don't slide smoothly against one another. Instead, the plates grind together and build up strains and stresses in the crust. This slow-motion collision is the source the region's numerous earthquakes and the creator of the volcanoes that make up the Aleutian Islands.

Importantly, the November 30 earthquake was not related to any volcanic activity, according to the Alaska Volcano Observatory. It also wasn't directly related to the subduction zone, explains Paul Caruso, a geophysicist with the U.S. Geological Survey.

“As the Pacific plate is pushing underneath Alaska, it's causing all kinds of other stresses and strains on the crust,” he says. Occasionally, these stresses build up so much, they must release and rupture a fault. “Then you have something like a hundred years or a hundred thousand years of motion happen in matter of seconds or minutes”—aka, an earthquake, Andrews says.

 

Cincinnati Enquirer

edited by kcontents

Magnitude 7 sounds large—why are so few fatalities expected?

Magnitude is a measure of an earthquake's energy release, and it can only tell you so much about what any given event feels like at the surface. Differences in regional geology and even the depth of the quake can affect how much the locals feel Earth's trembles.

While details are still emerging about the specific fault that let loose in this case, researchers believe that the rupture was centered relatively deep in the Earth, roughly 25 miles below the surface. That's good news for locals, says Caruso.

“Shallow quakes cause more shaking, so the depth of this quake actually contributed to less shaking,” he says. Damage is also limited thanks to the low population density of the city and the lack of high-rise buildings.

https://www.nationalgeographic.com/science/2018/11/powerful-alaska-earthquake-building-damage-fatalities

 kcontents