快乐海洋论坛

 找回密码
 注册
查看: 5995|回复: 17

[林间]第一次在Woods Hole感觉到地震

  [复制链接]
jlinwhoi 发表于 2011-8-24 22:58:22 | 显示全部楼层 |阅读模式
本帖最后由 jlinwhoi 于 2011-8-27 02:12 编辑

昨天是2011年8月23日。下午1点51分,我在Woods Hole的办公室电脑前工作,突然觉得所在的克拉克实验楼(Clark Lab)正在忽悠忽悠的左右晃动,很轻,但头有点晕。我赶紧卡表。“忽悠”持续了大约10多秒。

昨天我只感觉到“忽悠”的面波(surface wave),而没感觉到短促的首波(P 波)。这与我从前在夏威夷经历的近距离地震大不一样。近距离地震来时,短促的P 波很明显,然后才感觉到大振幅的面波。

地震后20分钟,电话铃开始响。先是所里传媒办公室(Media Office)的Joanne说开始收到附近居民的询问电话。然后是波士顿的第7频道电视台来电希望采访。

后来得知这次M=5.8级的地震发生在“中弗吉尼亚州地震区”(Central Virginia Seismic Zone,图1)。该地震为逆冲加走滑型(reverse oblique faulting),有可能发生在Spotsylvania断层附近(图2、图3)。

昨天的地震离Woods Hole有800公里之远,而且只有5.8级,我们竟然能感觉得到!这可能是因为美国东部活动断层较少,岩石圈较冷硬,地震波能量被吸收也少,因此波能传得较远。

地震后我上了美国地质调查局的网站,回答了“请告诉我们你感觉到了吗”(Did You Feel It?-Tell Us!)的问卷(http://earthquake.usgs.gov/earth ... 2311a/us/index.html)。这是我第一次回答该问卷。昨天有十万多美国网民填了该问卷。


图1 2011年8月23日的M=5.8级地震发生在上图中的“Central Virginia Seismic Zone”附近。(该图来源:美国地质调查局)



图2 该地震可能发生在名为“Spotsylvania”的断层附近。这些断层的历史似乎悠久、复杂。昨天地震的逆冲加走滑的震源机制基本上符合该地区的现代应力场。(该图来源:http://web.wm.edu/geology/virgin ... keStory.pdf?svr=www


图3 该地震可能发生在名为“Spotsylvania”的断层附近。(该图来源同图2)

本帖子中包含更多资源

您需要 登录 才可以下载或查看,没有帐号?注册

x
rossbyping 发表于 2011-8-25 09:33:52 | 显示全部楼层
我也感觉到了“忽悠”的面波(surface wave),不过我办公室另外一个人没感觉到。
dingmin 发表于 2011-8-25 10:33:04 | 显示全部楼层
我也感觉到了,ps同学在Renren上的留言:
“哇塞 为什么我觉得我现在在晃悠阿时不时地震了
我觉得我们楼在晃悠!!!!!
我们要逃出去了!!!!
电话联系
!~!!!!!”
disappear. 发表于 2011-8-25 11:09:05 | 显示全部楼层
8月23号的60-Second Science主题就是呼吁大家去USGS的网站上填写问卷,我也跑上去看了一眼
bing 发表于 2011-8-25 12:18:53 | 显示全部楼层
好在没有人员伤亡。
滚滚长江都是水 发表于 2011-8-25 21:54:40 | 显示全部楼层
another factor for an Mw 5.8 earthquake to be felt at 800 km away would be the site effects. Low density materials beneath the surface would amplify the ground motion than hard rocks.
徐敏 发表于 2011-8-26 08:16:17 | 显示全部楼层
我也平生第一次填写了那个do you feel it的问卷调查,我当时非常的兴奋,第一感觉就是地震,立马站起来往窗户外面望去,看看是不是发生在附近,毕竟我们附近前几个月也发生地震了。然后我掏出iphone,打开seismometer软件,为时已晚了。。。哈哈!
徐敏 发表于 2011-8-26 22:36:11 | 显示全部楼层
Image of the day on WHOI website, "We feel it"!!!



We Felt It Too
The Ocean Bottom Seismology Laboratory at WHOI led by John Collins specializes in building and operating seismometers to record ground-shaking seismic waves on the seafloor. The lab almost always has some sensors around that are being tested. On Tuesday, shortly before 2 p.m., engineers in the lab—Alan Gardner, Tim Kane and Ken Peal—felt an odd shaking. They immediately went to their testing platform, which fortunately held a sensor at the time. From it, they recovered this seismogram, which recorded the seismic waves from Tuesday's magnitude 5.8 earthquake that rumbled the East Coast. (Courtesy of Ocean Bottom Seismology Lab, Woods Hole Oceanographic Institution)

本帖子中包含更多资源

您需要 登录 才可以下载或查看,没有帐号?注册

x
SunZhen 发表于 2011-8-26 23:09:14 | 显示全部楼层
美国东部也地震,看来地球是不是在做松骨运动了?
RuChen 发表于 2011-8-27 10:39:37 | 显示全部楼层
本帖最后由 RuChen 于 2011-8-27 12:22 编辑

我在MIT的green building 也感觉到了,我坐在窗户旁边,桌子在晃,窗户在响。
有趣的是green building 里学地球物理的同学几乎全跑出去了,我们其它专业的学生都没有想到要出去。
Enson 发表于 2011-8-31 12:40:06 | 显示全部楼层
近年真实地震频发年啊
 楼主| jlinwhoi 发表于 2011-9-1 05:31:23 | 显示全部楼层
本帖最后由 jlinwhoi 于 2011-9-1 05:34 编辑

当地报纸《The Falmouth Enterprise》采访林老师:

"Virginia Earthquake Felt By Some Here"

By BRENT RUNYON
《The Falmouth Enterprise》,Vol. 121  No. 38, Friday, August 26, 2011

A 5.8 magnitude earthquake hit Virginia on Tuesday afternoon at 1:51, and a few minutes later many felt the earth move in Falmouth.

One of those observers, Jian Lin, a Woods Hole Oceanographic Institution geophysicist, is very familiar with earthquakes, having studied them for the past three decades.

“I was sitting in my office at my desk, typing on my computer and I felt it,” said Dr. Lin from his office at the Clark Laboratory on the Quissett Campus. “I definitely felt the swinging of the building, and being a scientist, I started to record the time. It lasted for 15 seconds.”

Down the street at the Broderick House on the Marine Biological Laboratory campus on North Street, Woods Hole, other scientists were on a conference call with colleagues in Washington, DC, when the earthquake hit there.

“They were in the middle of a sentence and suddenly there was this hollering,” said Robert J. Corrigan, director of project management for the Encyclopedia of Life. “We thought it was something like a bug had flown into the room, but they were clearly rattled on the other side.”

Mr. Corrigan said they soon realized that there was an earthquake, but never expected to feel it here. “Two minutes or so later, the building rocked gently back and forth, and outside I watched the trees do the same,” he said.

At Falmouth High School on Gifford Street Extension, a research-quality seismograph registered the earthquake. The seismograph was purchased in 2006 with a grant by the Falmouth Education Foundation for $7,000 to teach students about earthquakes.

Ryan Webber of the high school’s information technology department said he confirmed that the seismograph recorded the earthquake, but did not have the expertise to interpret the results.

Chairman of the Falmouth School Committee Rebecca R. Moffitt also said she felt the earthquake at her home on Worcester Court in Falmouth.

Seismographs in Falmouth also registered the earthquake and were recorded with thousands of other readings at the United States Geological Survey. Locally, seismographs measured between a 2.0 and 2.9 magnitude earthquake.

Researchers Alan T. Gardner, Timothy Kane, and Kenneth R. Peal were in John Collin’s ocean bottom seismology lab, which specializes in putting seismometers on the sea floor. All of them felt the quake and confirmed that it happened with a reading on one of the sensors they were testing.

“A single seismograph does not tell the magnitude of the earthquake but just the effect of the earthquake where the sensor is located,” Mr. Peal wrote in an e-mail. “In order to determine magnitude and location of the earthquake, seismologists look at seismograms from sensors at many different locations around the world. They then process this data together to calculate where the earthquake was centered and how big it was.”

Dr. Lin said Falmouth residents did not feel the sudden jolt associated with earthquakes, because the high frequency waves lose energy long before they crossed the long distance between Virginia and Massachusetts. What Falmouth residents felt was the low frequency waves that can travel much greater distances.

The crust of the East Coast of the United States is made of relatively solid rocks, unlike California, where the crust is broken up by many fault lines, Dr. Lin said. Earthquakes can travel a much greater distance on the East Coast than they can in California.

The earthquake on Tuesday registered as far away as Canada. “That is one of the most noticeable things about the earthquake,” Dr. Lin said. “That also has implications for the eastern United States. An earthquake of the same magnitude as one in California could cause much more significant damage here.”

Dr. Lin said he was not expecting to feel an earthquake here. “It was a surprise to me,” he said. “I have studied earthquakes for 30 years and I would not expect to feel an earthquake in Woods Hole.”

Dr. Lin said the largest recorded earthquake in Massachusetts history was in 1755, which is estimated at a 6.2 or 6.3 magnitude earthquake. Scientists are still not sure where exactly the fault lines are that caused that earthquake, he said.
汤民强 发表于 2011-9-1 22:29:16 | 显示全部楼层
上半年在成都的时候感受到几次小的四点几的地震,有次是午休的时候床轻微晃动了几下。地震还是不要感受的好,away、away~~
shang 发表于 2011-9-4 06:32:20 | 显示全部楼层
当时我在办公室里很明显的感觉到了 持续了很久 从开始到结束办公室里没一个人说话 全都坐在原位上
敏敏 发表于 2011-9-7 18:30:42 | 显示全部楼层
感到震动第一反应是掐表......哈哈 看到林老师掐表之后的分析,果然是专家\(^o^)/~我估计我要是经历地震的时候,应该是把当时的感觉像个文科生一样写段感慨...
张涛 发表于 2011-9-8 10:02:45 | 显示全部楼层
我们家号称在郯庐断裂边上,但是只有在上高中时候感觉过到一次地震。当时正在上自习,觉得楼在晃,就知道是地震了。因为老师提前说过,地震就几秒钟时间,跑都跑不掉,所以我们班全班都很淡定,继续复习有机化学。后来才知道,应该钻到桌子底下去。
liuweiyong 发表于 2011-9-8 18:50:42 | 显示全部楼层
林老师找地震找了这么久,还是被地震找到了
wdt 发表于 2011-9-10 09:11:38 | 显示全部楼层
我当时在马里兰,也感觉到了,不过因为是在地下室里,所以感觉不是特别明显,只是觉得整个房子有点晃,但是地面没有动,所以心里还怀疑了一下,是不是地震呀?但是我老公在办公室,三楼,他那里感觉就非常明显。不过有点汗颜,因为我觉得晃得不厉害,而且时间很短,所以第一反应不是跑出去,而是坐下来上USGS网站查是不是地震了。。。。。。。。
您需要登录后才可以回帖 登录 | 注册

本版积分规则

QQ|小黑屋|手机版|Archiver|快乐海洋论坛 ( 浙ICP备11010086号 )

GMT+8, 2019-11-14 06:06

Powered by Discuz! X3.4

© 2001-2017 Comsenz Inc.

快速回复 返回顶部 返回列表