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Earthquake Hazards Program images.

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Participants looking at laptops.
BMKG Training Participants on Laptops
BMKG Training Participants on Laptops
BMKG Training Participants on Laptops

Photo of participants working on training material on laptops.

The USGS training at the Bureau of Meteorology, Climatology and Geophysics (BMKG) includes hands-on activities. The BMKG staff are highly capable and have received an excellent educational background at the BMKG College or National University.

Photo of participants working on training material on laptops.

The USGS training at the Bureau of Meteorology, Climatology and Geophysics (BMKG) includes hands-on activities. The BMKG staff are highly capable and have received an excellent educational background at the BMKG College or National University.

Four people standing next to each other.
Dr. Walter Mooney with BMKG Participants
Dr. Walter Mooney with BMKG Participants
Dr. Walter Mooney with BMKG Participants

Dr, Walter Mooney with three Bureau of Meteorology, Climatology and Geophysics (BMKG) training participants in Palu, Sulawesi. 

Dr, Walter Mooney with three Bureau of Meteorology, Climatology and Geophysics (BMKG) training participants in Palu, Sulawesi. 

Photo of a black, square device with rounded corners on a green background
Accelerograph
Accelerograph
Accelerograph

Photo of a Kinemetrics FBA-23 accelerograph. The device is black and square with rounded edges on a green background.

Photo of a Kinemetrics FBA-23 accelerograph. The device is black and square with rounded edges on a green background.

A diagram with a labelled Benioff Zone beside red x's labelled as "earthquake focus" under an interaction of an oceanic and continental lithosphere.
Benioff Zone
Benioff Zone
Benioff Zone

Cross-section of the Benioff zone resulting from a by the interaction of a downgoing oceanic crustal plate with a continental plate.

Cross-section of the Benioff zone resulting from a by the interaction of a downgoing oceanic crustal plate with a continental plate.

Image of graph with seismic waves (squiggles) on it
earthquake seismogram.gif
earthquake seismogram.gif
earthquake seismogram.gif

When seismologists think of an earthquake, this image of a seismogram is what comes to their minds.

When seismologists think of an earthquake, this image of a seismogram is what comes to their minds.

Diagram of dipping slab with different focal depth events shown at different depths.
Focal Depth
Focal Depth
Focal Depth

Diagram of dipping slab with different focal depth events. The focal depth refers to the depth of an earthquake hypocenter.

Diagram of dipping slab with different focal depth events. The focal depth refers to the depth of an earthquake hypocenter.

Blurry table of the geologic time scale
Geologic Time Scale
Geologic Time Scale
Geologic Time Scale

The geologic time scale showing each eon, era, period, epoch, and their associated ages.

The geologic time scale showing each eon, era, period, epoch, and their associated ages.

Photo of a bridge over a valley with a semi-transparent textbox labelled "www.worldweb.com. Photo c Jim Forrest"
Bridge (Geotechnical)
Bridge (Geotechnical)
Bridge (Geotechnical)

Photo of bridge.  Geotechnical means referring to the use of scientific methods and engineering principles to acquire, interpret, and apply knowledge of earth materials for solving engineering problems.  

Photo of bridge.  Geotechnical means referring to the use of scientific methods and engineering principles to acquire, interpret, and apply knowledge of earth materials for solving engineering problems.  

Crustal block diagram with the down-dropped blocks labelled as "graben" and the upthrown blocks labelled as "horst" between faults
Horst and Graben Diagram
Horst and Graben Diagram
Horst and Graben Diagram

Horst and graben diagram. A graben is a down-dropped block of the earth's crust resulting from extension, or pulling, of the crust. 

Horst and graben diagram. A graben is a down-dropped block of the earth's crust resulting from extension, or pulling, of the crust. 

Map of Iceland showing plate boundaries
Iceland and Plate Motions (Kinematic)
Iceland and Plate Motions (Kinematic)
Iceland and Plate Motions (Kinematic)

Iceland and plate motions. Kinematic refers to the general movement patterns and directions of the earth's rocks that produce rock deformation.

Iceland and plate motions. Kinematic refers to the general movement patterns and directions of the earth's rocks that produce rock deformation.

Graph with scattered dots with a diagonal line going downward from left to right in between the dots
Least Squares Fit Plot
Least Squares Fit Plot
Least Squares Fit Plot

Plot showing least squares fit. When plotting data points on a graph, the least-squares-fit is the line or curve that comes closest to going through all the points.

Plot showing least squares fit. When plotting data points on a graph, the least-squares-fit is the line or curve that comes closest to going through all the points.

Two fault lines with circles showing their aftershocks
Landers Fault and Hector Mine Fault Aftershocks
Landers Fault and Hector Mine Fault Aftershocks
Landers Fault and Hector Mine Fault Aftershocks

The Landers fault (red lines at left) and the Hector Mine fault and its aftershocks (red lines and circles at right). The Hector Mine earthquake was a magnitude 7.1, and it produced thousands of aftershocks.

The Landers fault (red lines at left) and the Hector Mine fault and its aftershocks (red lines and circles at right). The Hector Mine earthquake was a magnitude 7.1, and it produced thousands of aftershocks.

Two graphs
Natural Frequency
Natural Frequency
Natural Frequency

The natural frequency is the frequency at which a particular object or system vibrates when pushed by a single force or impulse, and not influenced by other external forces or by damping. If you hold a slinky by one end and let it hang down and then give it one push up from the bottom, the rate of up-and-down motion is its natural frequency.

The natural frequency is the frequency at which a particular object or system vibrates when pushed by a single force or impulse, and not influenced by other external forces or by damping. If you hold a slinky by one end and let it hang down and then give it one push up from the bottom, the rate of up-and-down motion is its natural frequency.

Photo of large house with damage and debris on the ground
Los Gatos Residence Damage
Los Gatos Residence Damage
Los Gatos Residence Damage

This turn-of-the-century wooden residence in Los Gatos sustained major damage when it moved off its foundation during the October 17, 1989, M7.1 Loma Prieta, California earthquake.

This turn-of-the-century wooden residence in Los Gatos sustained major damage when it moved off its foundation during the October 17, 1989, M7.1 Loma Prieta, California earthquake.

Block diagram showing equal waves throughout
Surface Waves
Surface Waves
Surface Waves

A surface wave is a seismic seismic wave that is trapped near the surface of the earth.

A surface wave is a seismic seismic wave that is trapped near the surface of the earth.

Diagram of a right triangle representing land and a blue sqiggly line representing a sea wave
Tsunami Diagram
Tsunami Diagram
Tsunami Diagram

A tsunami is a sea wave of local or distant origin that results from large-scale seafloor displacements associated with large earthquakes, major submarine slides, or exploding volcanic islands.

A tsunami is a sea wave of local or distant origin that results from large-scale seafloor displacements associated with large earthquakes, major submarine slides, or exploding volcanic islands.

Diagram showing P waves (small jolt or light shaking or not felt), S waves (larger jolt or strong shaking), and surface waves (rolling motion))
P Waves
P Waves
P Waves

A P wave, or compressional wave, is a seismic body wave that shakes the ground back and forth in the same direction and the opposite direction as the direction the wave is moving.

A P wave, or compressional wave, is a seismic body wave that shakes the ground back and forth in the same direction and the opposite direction as the direction the wave is moving.

Black background with a green wave and a white arrow pointing across one concave and one convex hump to indicate a period
Period
Period
Period

Diagram of period.  The period is the time interval required for one full cycle of a wave.

Diagram of period.  The period is the time interval required for one full cycle of a wave.

Seismic waves
Seismic Waves
Seismic Waves
Seismic Waves

A seismogram is a record written by a seismograph in response to ground motions produced by an earthquake, explosion, or other ground-motion sources.

A seismogram is a record written by a seismograph in response to ground motions produced by an earthquake, explosion, or other ground-motion sources.

Diagram showing a descending slab in yellow with the associated dip angle, flow pressure, and gravitational body force vectors
Descending Slab
Descending Slab
Descending Slab

A slab is the oceanic crustal plate that underthrusts the continental plate in a subduction zone and is consumed by the earth's mantle.

A slab is the oceanic crustal plate that underthrusts the continental plate in a subduction zone and is consumed by the earth's mantle.

Diagram showing a blob shape with a D and an arrow pointing right and a labelled reupture.  The height is labelled "W" and the length is "L."  The top line is labelled "Surface" and the bottom line is labelled "Base of seismogenic zone"
Seismogenic Zone
Seismogenic Zone
Seismogenic Zone

Moment = ? A D

? = shear modulus = 32 GPa in crust, 75 GPa in mantle

A = LW = area

D = average displacement during rupture

Moment = ? A D

? = shear modulus = 32 GPa in crust, 75 GPa in mantle

A = LW = area

D = average displacement during rupture

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