ÖNCEL AKADEMİ: SOLID EARTH GEOPHYSICS
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Seismic tomography uses seismic wave data to image the interior of the Earth. It has improved our understanding of the Earth's structure over time. Modern seismic tomography provides high resolution global models of seismic wave speed variations that help answer questions about mantle dynamics, plate tectonics, and deep Earth structure.
![Solid Earth Geophysics-Geop503 Ali Oncel [email_address] Department of Earth Sciences, KFUPM Seismic Anisotropy Reading: Fowler Chapter 8- Section 8.1](https://image.slidesharecdn.com/lecture08-091219230641-phpapp02/85/ONCEL-AKADEMI-SOLID-EARTH-GEOPHYSICS-1-320.jpg)
ÖNCEL AKADEMİ: SOLID EARTH GEOPHYSICS
- 1. Solid Earth Geophysics-Geop503 Ali Oncel [email_address] Department of Earth Sciences, KFUPM Seismic Anisotropy Reading: Fowler Chapter 8- Section 8.1
- 2. Summary: Lecture 6 Seismic Tomography What does tomography reveal? Types of tomography Local Earthquake Tomography Teleseismic Tomography Data Global Seismographic Network Application Global Seismic Tomography
- 3. Seismic tomography is a very active and popular research field …Then, Seismic Imaging the Earth’s interior What is seismic/earthquake tomography ? What information can it provide? 5-Minutes
- 4. Progress in Knowledge of Earth KRAEMER (1902) 1903’s view of Earth BOLT (Inside the Earth, 1973) 1973’s view of Earth DZIEWONSKI (~1990, from www) 1999’s view of Earth 1800’s view of Earth
- 7. Global network for past 40 years
- 8. Data: Arrival Time Travel time tomography uses first-arrivals of body waves (P- and/or S-waves) Observation: Arrival time of first arrival Modified after from Dr. Stephan Husen’s lecture notes M4 earthquake close to Brugg, Station DAVOX
- 9. Broadband Seismometer Modified from www.nanometrics.ca
- 10. South American Earthquake on Oct. 28, 1997, at 06 H 15 M, epicenter located at 4.3 ° S, 76.6 ° W, depth = 124 km, magnitude = 6.5 This map shows the location of the first of the three earthquakes considered in the lab. The lines connecting the earthquake to the stations are great circles on a global Mercator projection. Source: EAS 388 Earthquake located here
- 11. Improvement in Seismic Stations What is the nature of upwellings within the deep mantle? Are there truly gaps in subducted slab within the lower mantle, as appears to be the case beneath East Asia? Do slabs continue to the core-mantle boundary, if so, how? What is the cause for the apparent difference in P and S velocity structure in the deepest mantle? Better models are within reach, given the large amount of high quality seismic data becoming available. Such models can reduce uncertainty in plate reconstructions and can help resolve questions such as: From: http://geo.web.ru/sbmg/sbor/tomography/Grand/grand.html
- 12. P-wave S-wave Global Seismic Tomography: A Snapshot
- 13. Map of Subduction Zones Present Past
- 14. Lower Mantle Both models show striking high wave-speed structures in the mid-mantle beneath the Americas and southern Eurasia. The two models agree in detail for the anomaly beneath the Americas. The fast anomaly stretches from 30°S to about 50°N beneath the central part of North America.
Editor's Notes
- #4: Overview
- #5: 1800’s view of Earth
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