REFERENCE: The Blue Planet An Introduction to Earth System Science. Brian J. Skinner and Barbara W. Murck (2011) Third Edition. John Wiley and Sons Inc.

An Earthquake is caused by sudden release of elastic energy stored in rocks.

Elastic deformation: Any change of shape or size that disappears when the deforming forces are removed.

The EPICENTER of an earthquake is the point of the Earth's surface that lies vertically above the focus.

The FOCUS of an earthquake is the site of first movement on a fault and the center of energy release.

When an earthquake occurs, the elastically stored energy is carried outward from the focus to other parts of the Earth by vibrations.

These vibrations are called seismic waves and spread out

spherically in all directions, just as sound waves.

Seismographs measure and record the vibrations associated with earthquakes.Modern seismographs use the principle of inertia—the resistance of a heavymass to motion. In this schematic diagram, seismic waves cause the supportpost and the roll of paper to vibrate back and forth, but the large massattached to the pendulum and the pen attached to it barely move at all.

Body Waves: Travel outward in all directions from the focus and have the capacity to travel through the Earth's interior.

P (primary) waves - compression/expansion

S (secondary) waves - shear

Surface Waves: Travel around but not through the Earth; they are guided by the Earth's surface.

Seismic hazard map - This is a seismic hazard map for North America, based on Peak Ground Acceleration, a

measure of ground motion due to seismic activity. The red and brown colors reflect more seismic activity, and they

are concentrated along the active plate margins of Central America, California, the Pacific Northwest, and Alaska.

However, there are a few other areas of high seismic risk located far from active plate margins.

“Durante el 2012 la RSPR localizó 2,851 sismos en el área local.”

“Durante agosto del 2014 la RSPR localizó 214 sismos en el área local.”

February 27, 2010 Magnitude=8.8

1. Aerial Photographs

2. Visible images collected by multispectral sensors (Ex. TM, IKONOS, ERS)

3. Synthetic Aperture Radar Interferometry (InSAR)

A series of powerful earthquakes rattled northern Japan starting on the evening of October 23. This IKONOS image shows a massive landslide over the EnokiTunnel.

Satellites Guide Relief to Earthquake Victims-On Thursday, May 28th of 2009, at 2:24 a.m. local time,

a deadly earthquake rocked Honduras, killing seven people and injuring several others, demolishing homes, damaging scores of other buildings, and sending terrified residents running through the streets.

San Andreas Fault

SPOT Image

Haiti Earthquake

Using InSAR we are able to map active ground displacements. This geodetic method uses two or more synthetic aperture radar (SAR) images to generate maps of surface deformation or digital elevation, using differences in the phase of the waves returning to the satellite or aircraft.

Detecting Earthquakes

with SatelliteImages obtained from satellite

radar contained two important

information. Information is

power transmit beam in the

form of phase and amplitude,

which is influenced by the

number of waves emitted and

reflected back. At the time of

the wave emitted performed

phase measurements. In the

images obtained from each

pixel, will have two

information. The intensity of

the signal can be used to

determine the characteristics

of a material that reflects the

wave, while the wave phase is

used to determine whether

there has been a movement

(deformation) on the surface

of the reflecting wave.

KARAKAX, TIBET

Obtained elevation data on a near-global scale. Generated the most complete high-resolution digital

topographic database of Earth. Consisted of a specially modified radar system that flew

onboard the Space Shuttle Endeavour during an 11-day mission in February of 2000.

An international project by the National Geospatial-Intelligence Agency (NGA) and NASA.

Shuttle Radar Topography Mission (SRTM)The SRTM radar consisted of a main antenna onboard the spaceshuttle and an outboard antenna located at the end of a 60 metermast. This separation measurement remains constant, andtherefore when the reflected radar signals reach the individualsensors, representing a single point where the radar reflected fromthe surface, accurate elevation of the earth’s surface can becalculated.

SAN ANDREAS AREA

This image of the world was generated with data from the Shuttle Radar Topography

Mission (SRTM). This image was created from that data set and shows the world

between 60 degrees south and 60 degrees north latitude, covering 80% of the Earth's

land mass. The image is in the Mercator Projection commonly used for maps of the

world. Two visualization methods were combined to produce the image: shading and

color coding of topographic height. The shade image was derived by computing

topographic slope in the northwest-southeast direction, so that northwest slopes appear

bright and southeast slopes appear dark. Color coding is directly related to topographic

height, with green at the lower elevations, rising through yellow and tan, to white at the

highest elevations. http://www2.jpl.nasa.gov/srtm/

• Interferometric map of the Hector Mine earthquake, shows the ground displacement along the radar line of sight. A full color cycle represents 10 cm of range displacement. Gray areas show zones of low phase coherence that have been masked before unwrapping.

• Thin solid lines within the zones of dense fringes are surface breaks from azimuth and range offsets.

• Data depicted here covers frames 2907 and 2925 of descending track 127.

Watch the YouTube video called

“How Earthquakes Work”