HOW ARE we “BLIND” TO some of our faults?

Slides:

Advertisements

Similar presentations

The Transverse Ranges LA in the Squeeze. The coastline from Ventura to Point Conception beyond Santa Barbara is unusual in that it faces south, not west,

Advertisements

New Views of the Seattle and Tacoma Faults Tom Brocher and Brian Sherrod U.S. Geological Survey Menlo Park, California and Seattle, Washington.

FAULTS OF THE LOS ANGELES FIELD TRIP. FAULTS OF THE LOS ANGELS FIELD TRIP  How were the San Gabriel Mountains uplifted? –Kim Gloersen  How the Raymond,

Active Folding within the L.A. Basin with a focus on: Argus et al. (2005), Interseismic strain accumulation and anthropogenic motion in metropolitan Los.

Active folding within LA Basin Readings: Shaw, J., and P. Shearer, An elusive blind-thrust fault beneath Metropolitan Los Angeles, Science, 283, 1516-

Faults in Focus: Earthquake Science Accomplishments Thomas H. Jordan Director, Southern California Earthquake Cente r 28 February 2014.

Section 1: Earth’s Crust in Motion How Do Stress Forces Affect Rock?

1 High Performance Computing at SCEC Scott Callaghan Southern California Earthquake Center University of Southern California.

The Violent Earth Faults, seismology, and the Bay Area.

Earthquake Predictibility, Forcasting and Early Warning Bill Menke October 18, 2005.

Earthquakes Movement & Destruction. What is an Earthquake? Shaking of the Earth produced by a sudden movement of rock beneath its surface.

UseIT Tutorial # 3 Earthquakes in the Southern California Fault System Tom Jordan June 16, 2011.

Measuring Earthquakes By: Lily and Assul. Earthquakes  They can release a huge amount of energy or a very little amount  It depends on how much rock.

Constructive & Destructive Forces

EARTHQUAKE An earthquake is a sudden, rapid shaking of the Earth caused by the release of energy stored in rocks. An earthquake is a sudden, rapid shaking.

Earthquakes A Whole Lot of shakin’ going on!. What are Earthquakes and where do they occur? Seismology is the study of earthquakes. Seismology is the.

Earthquakes Chapter 11 P. Lobosco

Lisa Wald USGS Pasadena U.S. Department of the Interior U.S. Geological Survey USGS Earthquake Hazards Program Earthquakes 101 (EQ101)

Earthquakes Chapter 2 book F page 44. Vocabulary for section 1 page 44 book F Stress Tension Compression Shearing Normal fault Reverse fault Strike-slip.

Section 1: Earth’s Crust in Motion How Do Stress Forces Affect Rock? The movement of earth’s plates creates powerful forces that squeeze or pull the rock.

Part 8: Fold Types. Tensional Stress Compressive Stress Shear Stress Orientation of stress leads to different folds.

California Earthquakes Through an historical perspective.

Kenneth W. Hudnut USGS, Pasadena, CA West Newport Beach Association Public Forum, Newport Beach City Hall March 5, 2003 Coping with ‘quakes.

Earthquakes: What are they and what causes them to happen?

NESC Academy 1 Unit 24 Seismic Shock. NESC Academy Nine people were killed by the May 1940 Imperial Valley earthquake. At Imperial, 80 percent of the.

LESSONS FROM PAST NOTABLE EARTHQUAKES. Part IV Walter Hays, Global Alliance for Disaster Reduction, Vienna, Virginia, USA.

Earthquakes! An earthquake, or seismic event, is a sudden movement of Earth’s crust that releases energy.

Faults and Earthquakes. Some faults become “locked” –Pressure pushes together the irregular walls of the fault; surfaces resist sliding Slip can’t occur.

California Geologic Regions and Hazards Presentation DAY 2.

The earth has “plates” and when two plates hit each other, one goes under and becomes “molten” which means it gets so hot, the g ground turns into liquid.

Constructive & Destructive Forces. EQ: What is the difference between a Constructive Force and a Destructive Force?

U.S. Department of the Interior U.S. Geological Survey The Earthquake is Inevitable: The Disaster is Not.

Earthquakes Vibrations of the earths crust Occur when rocks shift suddenly under a fault When friction prevents rocks from moving the fault is said to.

Earth’s Crust in Motion. Stress in the Crust Earthquake is the shaking and trembling that results from the movement of rock beneath Earth’s surface.

Essential Questions What is an Earthquake? What is a Tsunami? What Causes Earthquakes? What are the Effects of Earthquakes?

Earthquakes 101 (EQ101) Lisa Wald USGS Earthquake Hazards Program

Rocks Move along Faults

Earthquakes USGS Earthquake Hazards Program Earthquake Basics

Earthquakes: How do they happen

How were the San Gabriel Mountains Uplifted?

What are Earthquakes? The shaking or trembling caused by the sudden release of energy Usually associated with lithospheric plates moving against each other.

Earthquakes - Seismology

Section 4: Earthquakes and Society

Section: 1: Forces inside Earth

SAN ANDREAS FAULT San Francisco Bay Area North American plate

Earth’s Crust in Motion

Earthquakes California Standards 3.a., b., & c.

“It’s an earthquake”.

Understanding Earth Chapter 13: EARTHQUAKES Grotzinger • Jordan

DO NOW Pick up notes sheet..

Section 4: Earthquakes and Society

LA Basin Story Tectonics Geology Faults Velocity Structure Seismicity

Earthquakes and More.

Forces Within Earth Earthquakes are natural vibrations of the ground caused by movement along fractures in Earth’s crust, or sometimes, by volcanic eruptions.

There are more than 30,000 earthquakes worldwide each year!

UNIT 4 The theory of plate tectonics explains Earth’s geological processes

An____________is a movement of Earth’s lithosphere that occurs when rocks in the lithosphere suddenly shift, releasing stored energy. The energy released.

Earthquakes Vocab.

Chapter 5 Section 1 What processes change Earth’s crust?

Lesson 14: Plate Tectonics II Geological Oceanography

Plate Tectonics Tectonic plates are blocks of lithosphere that consist of the crust and the rigid, outermost part of the mantle and glide across the.

Ch. 13 Volcanoes Volcano: A vent or fissure in Earth’s surface through which magma and gases are expelled. Often volcanoes look like mountains.

Forces Within Earth Earthquakes are natural vibrations of the ground caused by movement along fractures in Earth’s crust, or sometimes, by volcanic eruptions.

Plate Tectonics II Geological Oceanography

Chapter 6, Lesson 1, Earthquakes and Plate Boundaries

Name: _____________________ Date:_____________ Block: ____

Presentation transcript:

HOW ARE we “BLIND” TO some of our faults? HANNAH SHAMLOO

Blind thrust faults Some faults do not break through the surface anywhere along their length -some faults are not easy to locate or study, often go unnoticed for many years -sometimes faults are ‘buried’ by deposition of material atop the surface trace during the period between surface ruptures -other times, faults simply do not reach the surface or diffuse into folds beneath surface -existence of this type of “blind” fault is usually expressed at surface as chain of hills or by folding of local rock formations, which is what we have here http://earthsci.org/processes/struct/equake1/EQCaseHistories.html

Puente hills thrust fault Recently discovered, 1999 Los Angeles Basin Runs about 40 km Three segments Slip rate 5mm/year 4 Major E.Q.’s last 11,000 years -so we are aware that Northridge Earthquake in 1994 was produced by blind thrust faulting -but I would like to focus on a fault system that is less well known, but going to be very damaging in the future -because blind faults aren’t easily discovered, the puente hills fault system was more recently discovered in 1999 through a borehole -it is an active fault located in los angeles basin -runs about 40 km in three north-dipping sections from the Puente Hills region in the SE to just south of Griffith Park the NW, overlain by folds -Los Angeles, Santa Fe Springs, and Coyote Hills -slip rate of 4.5-5mm/year or .20inch/year -large earthquakes on the fault are infrequent, but if it were to happen, it would be make a substantial impact -a simultaneous rupture of all three PHT segments would produce a Mw 7.1 earthquake. http://www.scec.org/research/030404dolan.html

Compared to Northridge… DANGER Compared to Northridge… Northridge’s E.Q. directed strongest shaking towards N to sparsely populated mountains PHT fault focuses its shaking toward downtown LA LA Basin amplifies shaking 15x stronger energy release -it has had 4 large earthquakes in the last 11,00 years from M7.2-7.5 -this fault focuses its shaking toward downtown LA, and ground motions from this event might be severely damaging -this fault’s shape and direction make it different from the one that triggered the Northridge earthquake in 1994 -while Northridge's quake directed it’s strongest shaking towards N to sparsely populated mountains -The frequency of a major rupture in the Puente Hills Fault is on the order of once per several thousand years. -This frequency of occurrence is relatively rare compared to the San Andreas fault -the highest magnitude in that range would be about fifteen times stronger than the 1994 Northridge Earthquake in terms of energy release. -the shaking would be much greater too because of the unconsolidated sediment -as tom jordan said, “northridge would look like a walk in the park” Viz Credits: Amit Chourasia

REFERENCES Marquis, John. "New Study Reveals The Behavior Of The Puente Hills Thrust Fault." New Study Reveals The Behavior Of The Puente Hills Thrust Fault. Southern California Earthquake Center, 4 Apr. 2003. Web. 18 June 2013. Maugh II, Thomas H. (May 26, 2005). "Big Fault Under L.A. Could Be Devastating". Los Angeles Times 26 May 2005. Web. 18 Jan. 2013 Shaw, John H., Andreas Plesch, James F. Dolan, Thomas L. Pratt, and Patricia Fore. "Puente Hills Blind-Thrust System, Los Angeles, California." Thesis. N.d. Bulletin of the Seismological Society of America, 16 Nov. 2001. Web. 18 Jan. 2013.