1. GLG110 Geologic Disasters and the Environment Instructors Professor Ramon ArrowsmithProfessor Amanda Clarke Email: ramon.arrowsmith@asu.edu clarke.glg110@asu.eduramon.arrowsmith@asu.educlarke.glg110@asu.edu Office: PSF-640 480-965-5081PSF-636 480-965-6590 Earthquake Intensity

2. http://www.xkcd.com/723/ Why tweets might get to you before earthquake waves would

4. Test with an M4.3 earthquake near Morgan Hill California (30 March 2009 10:40:29 am local time at epicenter)

5. 30 Mar 2009 17:40:29 -- origin time -- -------------------- 30 Mar 2009 17:40:48omfg, earthquake! 30 Mar 2009 17:40:49earthquake! 30 Mar 2009 17:40:51earthquake? morgan hill, ca 30 Mar 2009 17:40:53Whoa. Earthquake???? 30 Mar 2009 17:40:53earthquake! 30 Mar 2009 17:40:54EARTHQUAKE 30 Mar 2009 17:40:57Earthquake! 30 Mar 2009 17:40:58Earthquake? 30 Mar 2009 17:40:59in an earthquake 30 Mar 2009 17:41:00earthquake 30 Mar 2009 17:41:00Oooh. Earthquake. 30 Mar 2009 17:41:00I think that was an earthquake 30 Mar 2009 17:41:00thinks we're having an earthquake. http://plurk.com/p/luod5 30 Mar 2009 17:41:01Earthquake in Silicon Valley! Love 'em! 30 Mar 2009 17:41:01yay earthquake! 30 Mar 2009 17:41:01just felt a mild earthquake 30 Mar 2009 17:41:03anyone feel the earthquake? 30 Mar 2009 17:41:03earthquake just happened! 30 Mar 2009 17:41:04Earthquake 30 Mar 2009 17:41:06earthquake 30 Mar 2009 17:41:07EARTHQUAKE!!!! 30 Mar 2009 17:41:07earthquake! 30 Mar 2009 17:41:08earthquake now people? 30 Mar 2009 17:41:08EARTHQUAKE!!! 30 Mar 2009 17:41:08Earthquake!!!! 30 Mar 2009 17:41:08anyone in the Bay Area just feel the earthquake? 30 Mar 2009 17:41:08Earthquake! 30 Mar 2009 17:41:09Minor earthquake. Maybe a 4 30 Mar 2009 17:41:09EARTHQUAKE!!!!! 30 Mar 2009 17:41:09EARTHQUAKE IN SJSU!!! 30 Mar 2009 17:41:10Earthquake hits South San Jose!? 30 Mar 2009 17:41:10I feel an earthquake in Sunnyvale, CA right now. 30 Mar 2009 17:41:10Earthquake in Santa Clara... building shaking 30 Mar 2009 17:41:11OMG, EARTHQUAKE! 30 Mar 2009 17:41:11Earthquake here in SJ, monitors shaking in the office. 30 Mar 2009 17:41:12Um, pretty sure I just felt a teeny-tiny earthquake 30 Mar 2009 17:41:12Earthquake? 30 Mar 2009 17:41:14Okay, earthquake.... Scared the crap outta me just now. 30 Mar 2009 17:41:14Oh shit, there was just an earthquake! Today is just plain ol crazy 30 Mar 2009 17:41:14earthquake in process 30 Mar 2009 17:41:15earthquake 30 Mar 2009 17:41:15Just has a small earthquake in SF

6. 30 Mar 2009 17:41:31WHOA earthquake. 30 Mar 2009 17:41:31Holy shit. Now *that* was an earthquake 30 Mar 2009 17:41:31Is it an earthquake we just felt? 30 Mar 2009 17:41:31Minor Earthquake here in the SF Bay Area. No details yet. I can see others noting it as well. 30 Mar 2009 17:41:31Aaah! Earthquake!! 30 Mar 2009 17:41:32That earthquake just now was so small it almost isn't worth mentioning. 30 Mar 2009 17:41:32Damn! I totally just missed an earthquake because I was walking. 30 Mar 2009 17:41:32little earthquake? or big truck? 30 Mar 2009 17:41:32Earthquake! 30 Mar 2009 17:41:33earthquake! 30 Mar 2009 17:41:33Earthquake?? 30 Mar 2009 17:41:34just felt an earthquake sitting in Mtn View library... not too scarey (yet)! 30 Mar 2009 17:41:35was that just an earthquake or is our foundation giving out? 30 Mar 2009 17:41:35earthquake felt in morgan hill 30 Mar 2009 17:41:35OMG. Earthquake? 30 Mar 2009 17:41:35Wow, big earthquake! (East bay/milpitas) probably a 5.x? 30 Mar 2009 17:41:36Earthquake! 30 Mar 2009 17:41:37I think that was an earthquake #fb 30 Mar 2009 17:41:38Earthquake!! 30 Mar 2009 17:41:38WOOT! Earthquake! 30 Mar 2009 17:41:38Small earthquake in the Bay Area. Almost as if Godzilla came stomping down the street. 30 Mar 2009 17:41:38Whoa! Just had an earthquake!... 30 Mar 2009 17:41:39Earthquake here http://tmeet.me/XXTY9 30 Mar 2009 17:41:39Earthquake just now...Menlo Park, CA 30 Mar 2009 17:41:39Nice earthquake! 30 Mar 2009 17:41:39Earthquake! Nice 30 Mar 2009 17:41:39earthquake in Redwood City 30 Mar 2009 17:41:40Earthquake in los gatos 30 Mar 2009 17:41:40anyone else feel that #earthquake?????? 30 Mar 2009 17:41:41Hmm. Small earthquake? Redwood City, CA. Or big truck? 30 Mar 2009 17:41:41Me too! (Earthquake!) 30 Mar 2009 17:41:41earthquake! 30 Mar 2009 17:41:42either just had a small earthquake or the guy with the jackhammer outside my window hit the foundation! 30 Mar 2009 17:41:43Whoa earthquake! Not up yet here: http://quake.usgs.gov/recenteqs/ 30 Mar 2009 17:41:44Earthquake in Santa Clara. Not major - 3 seconds of slight wobbling...

7. 30 Mar 2009 17:41:55Felt my first earthquake! 30 Mar 2009 17:41:55Earthquake! Just rumbled through 1 min ago here in San Jose! Nice little shake up! 30 Mar 2009 17:41:55Yay! Earthquake! 30 Mar 2009 17:41:55Earthquake! 30 Mar 2009 17:41:56just felt that special feeling; an earthquake. Gives me that little rush of adrenaline. Didn't bolt for a doorway, so not too big. 30 Mar 2009 17:41:56cat curled up in my arm didn't like that earthquake 30 Mar 2009 17:41:57Wow, #earthquake in San Jose. That was a shaker! 30 Mar 2009 17:41:57earthquake!.. in mt. view now.. that was a small cute one... 30 Mar 2009 17:41:57Just felt an earthquake at my desk! (in Mountain View) #google 30 Mar 2009 17:41:58Earthquake! 30 Mar 2009 17:41:59Ummm, HELLO!!! Huge earthquake! 30 Mar 2009 17:41:59Earthquake! 30 Mar 2009 17:42:00earthquake 30 Mar 2009 17:42:00well what do you know... an earthquake 30 Mar 2009 17:42:01Just had a little earthquake! 30 Mar 2009 17:42:02Earthquake just now in San mateo? 30 Mar 2009 17:42:03Earthquake ahhhhh!! 30 Mar 2009 17:42:03If I'm not mistaken, Silicon Valley just had an earthquake. Not the Big One. Just big enough to be felt. 30 Mar 2009 17:42:03woo hoo, just had a little earthquake 30 Mar 2009 17:42:06Just felt an earthquake. 30 Mar 2009 17:42:06Just felt a very teeny tiny earthquake, unless I have monsters under my bed 30 Mar 2009 17:42:07ditto on the earthquake from santa cruz 30 Mar 2009 17:42:08Wants to know what's shakin'... oh wait, that was an earthquake! 30 Mar 2009 17:42:08earthquake in Menlo Park! - Some excitement for Sand Hill Rd this am. Heidi says 4.0 30 Mar 2009 17:42:08OH SHIT!!!! EARTHQUAKE!!!!! 30 Mar 2009 17:42:09Whoa, I felt a little earthquake or a giant dog just humped the building. Did anyone else feel that? 30 Mar 2009 17:42:09Just felt an earthquake 30 Mar 2009 17:42:09Whoa. Earthquake!! 30 Mar 2009 17:42:10Just experienced an earthquake here in Sunnyvale, CA 30 Mar 2009 17:42:1010:40 Just felt an earthquake. Always fun, eh? 30 Mar 2009 17:42:11EARTHQUAKE!!!!!!! 30 Mar 2009 17:42:11Small earthquake here in Sunnyvale 30 Mar 2009 17:42:13Woo! Earthquake...how's that for exciting... 30 Mar 2009 17:42:13Well, that was an earthquake. 30 Mar 2009 17:42:13just felt the earthquake. Neato! 30 Mar 2009 17:42:14earthquake in Sunnyvale 30 Mar 2009 17:42:14earthquake - just felt a 5 sec tremor in SF 30 Mar 2009 17:42:18 did you feel the earthquake? just shookm... san jose 95134

8. Morgan Hill California example: extracting all geocoded tweets containing the word “earthquake” within a 200-km radius of the event.

9. “The potential response time for a Twitter-based earthquake detector is impressive. The typical delay for tweet transmission, according to Twitter engineers, is about five seconds. By running a simple automatic algorithm, the Morgan Hill earthquake could have been detected in under a minute. How does this compare to current U.S. Geological Survey response time? Currently, the Northern California Seismic Network (NCSN) releases earthquake information faster than any network contributing to the Advanced National Seismic System (ANSS). The first solution issued by the NCSN is an automatic “quick look” solution that has a hypocenter but no magnitude. For the Morgan Hill earthquake, the quick look solution was released in 22 seconds.”

10. USGS did you feel it? For Morgan Hill event

11. http://www.youtube.com/watch?v=ug-vjWEKBGg

12. http://miguelrios.tumblr.com/post/ 9338564551/spread-of- earthquake-related-tweets 40,000 tweets in the first minute after the earthquake http://173.254.16.66/rnd/quake- map/?size=large http://blog.socialflow.com/post/712024413 2/all-shook-up-mapping-earthquake-news- on-twitter-from-virginia-to-maine

13. Time of first identified earthquake tweet per unique identified location vs. distance of that location from epicenter, we can see a clear clustering form around the earthquake’s path. The points further away (above the red line) represent people responding to those experiencing the quake. The slope of the line aligns well with the speed at which the quake is estimated to have spread (around 3km/s).

14. http://earthquake.usgs.gov/earthquakes/dyfi/events/se/082311a/us/index.html

15. Earthquake Intensity – What We Feel During an Earthquake Mercalli intensity scale was developed to quantify what people feel during an earthquake Used for earthquakes before instrumentation or current earthquakes in areas without instrumentation Assesses effects on people and buildings Did You Feel It?: Maps of Mercalli intensities can be generated quickly after an earthquake using people’s input to the webpage http://pasadena.wr.usgs.gov/shake http://pasadena.wr.usgs.gov/shake Giuseppe Mercalli (the director of the Vesuvius Observatory)

16. The following is an abbreviated description of the 12 levels of Modified Mercalli intensity. I. Not felt except by a very few under especially favorable conditions. II. Felt only by a few persons at rest, especially on upper floors of buildings. III. Felt quite noticeably by persons indoors, especially on upper floors of buildings. Many people do not recognize it as an earthquake. Standing motor cars may rock slightly. Vibrations similar to the passing of a truck. Duration estimated. IV. Felt indoors by many, outdoors by few during the day. At night, some awakened. Dishes, windows, doors disturbed; walls make cracking sound. Sensation like heavy truck striking building. Standing motor cars rocked noticeably. V. Felt by nearly everyone; many awakened. Some dishes, windows broken. Unstable objects overturned. Pendulum clocks may stop. VI. Felt by all, many frightened. Some heavy furniture moved; a few instances of fallen plaster. Damage slight. VII. Damage negligible in buildings of good design and construction; slight to moderate in well-built ordinary structures; considerable damage in poorly built or badly designed structures; some chimneys broken. VIII. Damage slight in specially designed structures; considerable damage in ordinary substantial buildings with partial collapse. Damage great in poorly built structures. Fall of chimneys, factory stacks, columns, monuments, walls. Heavy furniture overturned. IX. Damage considerable in specially designed structures; well-designed frame structures thrown out of plumb. Damage great in substantial buildings, with partial collapse. Buildings shifted off foundations. X. Some well-built wooden structures destroyed; most masonry and frame structures destroyed with foundations. Rails bent. XI. Few, if any (masonry) structures remain standing. Bridges destroyed. Rails bent greatly. XII. Damage total. Lines of sight and level are distorted. Objects thrown into the air.

17. Earthquake Intensity – What We Feel During an Earthquake Mercalli scale variables: Earthquake magnitude –Bigger earthquake, more likely death and damage Distance from hypocenter –Usually (but not always), closer earthquake  more damage Type of rock or sediment making up ground surface –Hard rock foundations vibrate from nearby earthquake body waves –Soft sediments amplified by distant earthquake surface waves –Steep slopes can generate landslides when shaken

18. A Case History of Mercalli Variables San Fernando Valley, California, Earthquake of 1971 Earthquake magnitude –Magnitude 6.6, with 35 magnitude 4.0 or higher aftershocks in 7 minutes after main shock Distance from epicenter –Bull’s-eye damage pattern Building style –‘Soft’ first-story buildings were major problem –Hollow-core bricks at V.A. Hospital caused collapse –Collapse of freeway bridges

19. Did You Feel It? Citizens Contribute to Earthquake Science http://pubs.usgs.gov/fs/2005/3016/pdf/FS-2005-3016.pdf

20. Did You Feel It? Citizens Contribute to Earthquake Science http://pubs.usgs.gov/fs/2005/3016/pdf/FS-2005-3016.pdf

23. Intensity distributions at the same spatial scale Intensity is shaking in an earthquake at a point. It can vary with position. Magnitude is the measure of energy released in an earthquake.

24. http://blog.twitter.com/2011/06/global-pulse.html