Pelatihan : Techniques in Active Tectonic Study Juni 20-Juli 2, 2013 Instruktur: Prof. J Ramon Arrowsmith (JRA) Dari Arizona State University (ASU) - US Tempat Pelaksanaan: Ruang Pangea, Laboratorium Gempabumi (LabEarth) – Puslit Geoteknologi LIPI dan Kuliah lapangan akan dilakukan disekitar Sesar Lembang, Jawa Barat. * Lebih jelas baca TOR/KAK dan daftar acara

Why tweets might get to you before earthquake waves would

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

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

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

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

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

“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.”

USGS did you feel it? For Morgan Hill event

/spread-of- earthquake-related-tweets 40,000 tweets in the first minute after the earthquake map/?size=large 2/all-shook-up-mapping-earthquake-news- on-twitter-from-virginia-to-maine

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).