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Derivation of the Equations of Motion
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Monthly Archives: January 2015
The Seismicity of Iran
I showed you three important sources for global information on earthquake activity in class last week (USGS, ISC, GCMT). I am writing a proposal and had to make a map of recent earthquakes in Iran. The result is below. Iran is one of the most seismically active continental regions of the world.
Gray focal mechanisms represent earthquakes between 1976 and 1999; red mechanisms represent earthquakes from 2000-July, 2012 (source: GCMT). The red circles represent earthquakes since 2000 (source: ISC). The color bar shows elevation and bathymetry in meters.
The World Stress Map Project
Today I will introduce continuum mechanics with a discussion of stress, strain, and the equations of motion. Stress shows up in two (related) places in earthquake seismology. First, it is a critical component of the analysis of faulting processing, second, it is an essential element of the understanding of the propagation of seismic (stress) waves. We will look at each aspect in detail as we move forward in class. To get a handle on the patterns of tectonic stresses introduced by plate tectonics, visit this site and read the two papers that I placed on ANGEL.
Source: http://dc-app3-14.gfz-potsdam.de/pub/stress_data/stress_data_frame.html
Recent Earthquakes
I generally track earthquake occurrence using my iPad app. Recently I wrote a python code to summarize some information on large earthquake activity. The table below shows what’s been happening lately.
The unusual aspect is the very small number of earthquakes with magnitudes of six or larger during the last 30 days. Four is an unusually quiet period.
Great Earthquakes (last three years) 8.2 mww 2014-04-01 23:46:47 / 288 days - 94km NW of Iquique, Chile (25 km) 8.3 Mw 2013-05-24 05:44:49 / 601 days - Sea of Okhotsk (609 km) 8.0 Mw 2013-02-06 01:12:27 / 708 days - 76km W of Lata, Solomon Islands (29 km) 8.2 mwc 2012-04-11 10:43:10 / 1009 days - off the west coast of north Sumatra (25 km) 8.6 mww 2012-04-11 08:38:36 / 1009 days - off the west coast of north Sumatra (20 km) Major and Great Earthquakes (last year) 7.1 mww 2014-11-15 02:31:41 / 61 days - 155km NW of Kota Ternate, Indonesia (45 km) 7.1 mww 2014-11-01 18:57:22 / 75 days - 144km NE of Ndoi Island, Fiji (434 km) 7.3 mww 2014-10-14 03:51:34 / 93 days - 74km S of Intipuca, El Salvador (40 km) 7.0 mww 2014-10-09 02:14:31 / 98 days - Southern East Pacific Rise (17 km) 7.9 mww 2014-06-23 20:53:09 / 205 days - 19km SE of Little Sitkin Island, AK (109 km) 7.5 mww 2014-04-19 13:28:00 / 271 days - 70km SW of Panguna, Papua New Guinea (43 km) 7.2 mww 2014-04-18 14:27:24 / 272 days - Guerrero, Mexico (24 km) 7.4 mww 2014-04-13 12:36:19 / 277 days - 112km S of Kirakira, Solomon Is. (39 km) 7.6 mww 2014-04-12 20:14:39 / 277 days - 93km SSE of Kirakira, Solomon Is. (22 km) 7.1 mww 2014-04-11 07:07:23 / 279 days - 56km WSW of Panguna, Papua New Guinea (61 km) 7.7 mww 2014-04-03 02:43:13 / 287 days - 53km SW of Iquique, Chile (22 km) 8.2 mww 2014-04-01 23:46:47 / 288 days - 94km NW of Iquique, Chile (25 km) Recent Earthquakes (last 30 days) 6.6 mwp 2015-01-07 05:07:08 / 8 days - 245km S of Punta de Burica, Panama (10 km) 6.1 mwb 2014-12-30 21:17:23 / 15 days - 37km NNE of Ndoi Island, Fiji (598 km) 6.1 mwp 2014-12-29 09:29:41 / 17 days - 112km SSE of Cagayancillo, Philippines (38 km) 6.3 mww 2014-12-21 11:34:13 / 25 days - 156km WNW of Tobelo, Indonesia (41 km)
GEOSC 559 Earthquake Information Blog
My goal for this “blog” is that it be a dynamic information exchange for students studying earthquake science at Penn State. The core writers this semester are the students enrolled in GEOSC 559.But I have opened the blog up to others in the department that have interests.
Focus on earthquake science, but use it for the exchange of information on any related topic (mathematics, computing, etc.). Just keep the focus on items related to earthquake science.