1. Earthquakes and crustal Deformation - Objectives of class-
Introduce a variety of techniques to describe ‘quantitatively’ deformation of the lithosphere and fault slip history.
Introduce the basic mechanisms governing lithospheric deformation and conceptual models of the ‘seismic cycle’.
Introduce a number of modeling tools commonly used in tectonics studies.
I will try to lead you to think not only in terms of kinematics but also in terms of stress and rheology.

3. What factors determine the seismic potential of subduction zone?
Subduction rate?
Sea floor age?
Sea floor roughness?
Sediments?
A combination of these factors?
(Heuret et al,G3, 2011)

7. Plate motion of India relative to Eurasia
(Copley et al, 2010)

8. Topography and seismicity suggests continental
deformation is distributed

9. Velocities relative to Eurasia,
Where are the active faults?
Velocities relative to Eurasia,
Bettinelli et al (2006), Calais et al (2006), Simons et al (2007), Gan et al (2007), Chlieh et al (2010)

10. Satellite Mosaic and topography of Central Asia
The response is in the landscape

11. (Tapponnier and Molnar, 1975)

12. To do this, we use geodetic data, mainly GPS with one swath of insar, and also earthquake data. See India colliding into Asia, Tibetan plateau, steep front.
From this GPS we first look at the strain rate across the region to check which areas have the greatest strain rate buildup, so seismic hazard.

13. Strain Rate from GPS
The most obvious feature is the main himalayan thrust fault, stretching about 2000km in an arcuate shape. This is the main area of hazard. We can also see a few other mountain ranges, the Tien Shan, and this one, and some strike slip faults on the Tibetan plateau, including the Atlyn Tagh and this fault, but these are minor compared to the frontal thrust., so we focus on that.
- What fraction of geodetic strain is elastic and building up stresses to be released in future earthquakes?
- Is ‘interseismic strain ‘stationnary’

15. Some outstanding issues in Active Tectonics
Is continental deformation distributed or localized?
What factors determine the seismic potential of a fault, a faults system or a plate boundary?
What factors determine the relative proportion of seismic and aseismic slip on a fault?
How do earthquakes initiate?
What determines how large an earthquake will end once seismic rupture is initiated?
How can we probe the stress distribution on faults?
What factors determine the level of ground shaking?
What factors determine sea floor displacement (hence the tsunamigenic potential) during a subduction earthquake?
How are fluids involved in fault dynamics?

16. Why should we care about fluids?
The brittle crust is permeated with fluids of various nature (water, brines, gas) and various origin (meteoric, formation fluids, metamorphic fluids)
Direct observations showing that fluids can induce earthquakes.
We would like to understand better the relationship between seismicity and fluid flow for Geothermy, Oil and Gas recovery, CO2 storage…

17. Seismic Hazard Analysis, Current Practice
Where do earthquakes occur?
How often will they happen and how large can they get?
How hard will they shake the ground?
When answers are available for Steps 1-3: Add up all of the sources to find the probability of exceeding damaging shaking.

18. Hazard model for the central and eastern U. S
Hazard model for the central and eastern U. S. primarily based on past seismicity
What rate of earthquakes should be expected in the future?
(Ellsworth, Science, 2013)

19. Hazard model for the central and eastern U. S
Hazard model for the central and eastern U. S. primarily based on past seismicity
Higher rate of earthquakes implies higher hazard.
But how much higher?
And where has the hazard increased?
(Ellsworth, Science, 2013)

20. What information/observations do we need to make progress on these issues?
Good kinematic description of crustal deformation and fault behavior :
active faults
long-term slip rates,
Information about mode of slip (paleoseismo, paleogeodesy)
coseismic slip models
interseismic strain and interseismic coupling models…
Constraints on rheology of faults zone and the crust
Constraints on stresses…

21. Dynamic Modeling the Parkfield EQs Sequence on the San AF
[Barbot et al, Science, 2012]
How to calibrate and validate such models?

22. Earthquakes and crustal Deformation - Outline of class-
Day 1: Methods to identify and characterize active faults
Day 2: From kinematic to dynamic modeling
Day 3: Some case studies

23. I. Introduction
II. Methods in Morphotectonics
III. Methods in Geodesy an Remote sensing
IV. Relating strain, surface displacement and stress, based on elasticity
V. Fault slip vs time
VI. Learnings from Rock Mechanics
VII. Case studies

24. Day 1: Observing active faults
Identification of active faults
Fault slip rates from geomorphology
Paleoseismology and paleogeodesy
Geodetic and remote sensing techniques
Day 2: From fault kinematics to faults dynamics
Phenomenology of seismic and aseismic slip
Fault friction and dynamic modeling of the ‘seismic cycle’
The role of fluids
Day 3: Case Examples