Seismic Hazard in the United States Open Lecture Seminar JNES/IAEA - PowerPoint PPT Presentation

Seismic Hazard in the United States Open Lecture Seminar JNES/IAEA Kashiwazaki Seismic Symposium Niigata Institute of Technology Dr. Annie Kammerer, P.E. November 2010 1

Nuclear Renaissance 2

Recent Earthquakes & Existing US plants Plants Earthquakes 3

Fault Map of California

Diablo Canyon Nuclear Plant San Luis Obispo California 5

Fault Map of California Santa Barbara 6

Dr. Hardebeck USGS

Plate Tectonics 8

USGS Global Tectonics Map 9

Tectonic Map of Japan Faults and earthquakes 1900-2007 10

USGS Global Tectonic Map 11

Global Seismicity NASA DATM 12

US National Seismic Hazard Map 13

WHY? 14

Super continent Gondwana and Pangea just before the formation of the Atlantic Ocean Atlantic Geoscience Society 15

Video: Formation of the US Images Courtesy of Ron Blakey, Northern Arizona University compiled for this presentation by Greg Willis of the Northern Virginia Community College 16

Separation of the Super Continents Rifting that formed Atlantic Ocean 17

Surface rift zones in the U. S. (in purple) 18

Surface rift zones in the U. S. (in purple) 19

Bouguer gravity map of United States 20

Bouguer gravity map of United States 21

Plate Boundary General Tectonic Zones Mountain Building Failed Rifts Meteor Impact 22

Plate Boundary National Seismic Hazard Map Mountain Building Failed Rifts Meteor Impact 23

10,000 years ago 18,000 years ago North American Glaciations 24

Subduction of the Farallon Plate Figures by NASA and Levander et al (1999) 25

Figures by University of Munich and Wannamaker et al. Subduction of the Farallon Plate 26

Earthquakes in New Madrid United States Geological Survey 27

Intensity Map of New Madrid Earthquake 1811 USGS Prediction Actual Map of Observations National Earthquake Information Center 28

29

Quarternary Fault and Fold Database United States Geological Survey 30

Damaging Earthquakes 1750 to 1996 United States Geological Earthquakes 31

But, we have to build things so … WHAT DO WE DO? 32

Basic steps in seismic hazard … • Characterize all possible earthquake sources that may cause shaking at your location • Determine the level of shaking those sources can cause at your location 33

To characterize the sources and develop a regional source model, you need to synthesize many kinds of data Gravity Paleo- Magnetics seismic Tectonics GPS Crustal Geology stress Source Crustal Seismicity model geophysics 34

Often data doesn’t agree or the picture is incomplete, so a logic tree is used to show alternative models Magnetics Tectonics Gravity Branch Branch Branch Paleo- Geology seismic 1 2 3 Source Seismicity Characterization GPS model Branch option 1 Branch Option 1 Branch option 2 Source Branch Branch Option 2 option n 35

Data types • Recorded & historic seismicity • Geology • Tectonics • Magnetics • Gravity • GPS trace • Crustal Stresses • Surface geophysics • Paleoseismic 36

Data types • Recorded & historic seismicity • Geology • Tectonics • Magnetics • Gravity • GPS trace • Crustal Stresses • Surface geophysics • Paleoseismic 37

Data types • Recorded & historic seismicity • Geology • Tectonics • Magnetics • Gravity • GPS trace • Crustal Stresses • Surface geophysics • Paleoseismic 38

Data types • Recorded & historic seismicity • Geology • Tectonics • Magnetics • Gravity • GPS trace • Crustal Stresses • Surface geophysics • Paleoseismic 39

Data types • Recorded & historic seismicity • Geology • Tectonics • Magnetics • Gravity • GPS trace • Crustal Stresses • Surface geophysics • Paleoseismic 40

Data types • Recorded & historic seismicity • Geology • Tectonics • Magnetics • Gravity • GPS (geodetics) • Crustal Stresses • Surface geophysics • Paleoseismic 41

Data types • Recorded & historic seismicity • Geology • Tectonics • Magnetics • Gravity • GPS trace • Crustal Stresses • Surface geophysics • Paleoseismic 42

Data types • Recorded & historic seismicity • Geology • Tectonics • Magnetics • Gravity • GPS trace • Crustal Stresses • Surface geophysics • Paleoseismic 43

Data types • Recorded & historic seismicity • Geology • Tectonics • Magnetics • Gravity • GPS trace • Crustal Stresses • Surface geophysics • Paleoseismic 44

There are two general types of sources • Fault sources • Area sources Site – Also called distributed seismicity or background sources – Session on distributed Area Source seismicity at the workshop 45

Characterization of Area Sources Figure from Hardebeck (USGS) 46

Magnitude recurrence relationships Annual Rate of Earthquakes 3 4 5 6 7 8 Earthquake Magnitude 47

So we now know about the earthquake sources, but … WHAT DOES IT MEAN TO ME? 48

Ground motion prediction equations Acceleration (g) Peak Ground 49

Uncertainty • Aleatory variability – Randomness inherent in nature • Epistemic uncertainty – Model uncertainty resulting from incomplete data, not fully understanding the processes involved, or from using a simplified model 50

New Japanese code for nuclear plant accounts for uncertainty and beyond design basis ground motions • Assesses plants for earthquake motions beyond what the extreme events used for design and review • Very important for increased safety • Acknowledges that an exceedance can occur (though highly unlikely) 51

We have the sources, we have ground motion prediction equations … WHAT NOW? 52

Deterministic seismic hazard assessment • “Worst case” scenario analysis based on known faults • Need both fault information (seismic source characterization) • … and ground motion prediction equations • Challenging to determine the worst case • Uncertainty in fault addressed through conservative assumptions 53

Probabilistic seismic hazard assessment Find effects of all possible earthquakes, multiply each by the likelihood it will actually happen, combine the events 54

Once we have the ground motion levels, we can design the plants • Design of the plants includes a lot of “seismic margin” • This means that the structures, systems, and components can survive loads much high then the design shaking levels • This is why the KKNPP performed well, even given very high shaking levels 55

Also use defense-in-depth approach • Redundancy in systems • Design well, but plan actions to be taken in unlikely situations • Multiple layers of defense and containment to fully contain nuclear materials in worse cases 56

US actions in response • The 2007 earthquake had lessons for the NRC as well • Currently implementing “ShakeCAST” system to improve preparedness, situational awareness, and our ability to get information to the public 57

Questions? 58