Earth quakes Costa del Sol [enlarge]
Earthquakemonitor worldwide:
Earthquakemap of the last 31 days:
Newest  24 hoursn  1  4 days  4  7 dayse  7  31 days
The earthquake monitor
searches during day time every half hour (during night time not so
frequent) on
the Web for earthquake information and makes a detailed listing. I
also make
sure that little tremors
after a big earthquake are reported (force 2).
European Macroseismic Scale

The Richter Magnitude Scale The Richter scale is not a physical device, but a mathematical formula. The magnitude of an earthquake is determined from the logarithm of the amplitude of waves recorded on a seismogram at a certain period. Earthquakes are recorded by a seismographic network. Each seismic station in the network measures the movement of the ground at the site. The slip of block of rock over another in an EQ releases energy that makes the ground vibrate. That vibration pushes the adjoining piece of ground and cause it to vibrate and thus the energy travel out from the EQ in a wave. There are many different ways to measure different aspects of an earthquake. Magnitude is the most common measure of an earthquake's size. It is a measure of the size of the earthquake source and is the same number no matter where you are or what the shaking feels like. The Richter scale measures the largest wiggle on the recording, but other magnitude scales measure different parts of the earthquake. Intensity is a measure of the shaking and damage caused by the earthquake, and this value changes from location to location.
Seismic waves are the vibrations from earthquakes that travel through the Earth; they are recorded on instruments called seismographs. Seismographs record a zigzag trace that shows the varying amplitude of ground oscillations beneath the instrument. Sensitive seismographs, which greatly magnify these ground motions, can detect strong earthquakes from sources anywhere in the world. The time, locations, and magnitude of an earthquake can be determined from the data recorded by seismograph stations. The Richter magnitude scale was developed in 1935 by Charles F. Richter of the California Institute of Technology as a mathematical device to compare the size of earthquakes. The magnitude of an earthquake is determined from the logarithm of the amplitude of waves recorded by seismographs. Adjustments are included for the variation in the distance between the various seismographs and the epicenter of the earthquakes. On the Richter Scale, magnitude is expressed in whole numbers and decimal fractions. For example, a magnitude 5.3 might be computed for a moderate earthquake, and a strong earthquake might be rated as magnitude 6.3. Because of the logarithmic basis of the scale, each whole number increase in magnitude represents a tenfold increase in measured amplitude; as an estimate of energy, each whole number step in the magnitude scale corresponds to the release of about 31 times more energy than the amount associated with the preceding whole number value. At first, the Richter Scale could be applied only to the records from instruments of identical manufacture. Now, instruments are carefully calibrated with respect to each other. Thus, magnitude can be computed from the record of any calibrated seismograph. Earthquakes with magnitude of about 2.0 or less are usually called microearthquakes; they are not commonly felt by people and are generally recorded only on local seismographs. Events with magnitudes of about 4.5 or greater  there are several thousand such shocks annually  are strong enough to be recorded by sensitive seismographs all over the world. Great earthquakes, such as the 1964 Good Friday earthquake in Alaska, have magnitudes of 8.0 or higher. On the average, one earthquake of such size occurs somewhere in the world each year. The Richter Scale has no upper limit. Recently, another scale called the moment magnitude scale has been devised for more precise study of great earthquakes. The Richter Scale is not used to express damage. An earthquake in a densely populated area which results in many deaths and considerable damage may have the same magnitude as a shock in a remote area that does nothing more than frighten the wildlife. Largemagnitude earthquakes that occur beneath the oceans may not even be felt by humans.
The Modified Mercalli Intensity Scale The effect of an earthquake on the Earth's surface is called the intensity. The intensity scale consists of a series of certain key responses such as people awakening, movement of furniture, damage to chimneys, and finallytotal destruction. Although numerous intensity scales have been developed over the last several hundred years to evaluate the effects of earthquakes, the one currently used in the United States is the Modified Mercalli (MM) Intensity Scale. It was developed in 1931 by the American seismologists Harry Wood and Frank Neumann. This scale, composed of 12 increasing levels of intensity that range from imperceptible shaking to catastrophic destruction, is designated by Roman numerals. It does not have a mathematical basis; instead it is an arbitrary ranking based on observed effects.
The Modified Mercalli Intensity value assigned to a specific site after an earthquake has a more meaningful measure of severity to the nonscientist than the magnitude because intensity refers to the effects actually experienced at that place. After the occurrence of widelyfelt earthquakes, the Geological Survey mails questionnaires to postmasters in the disturbed area requesting the information so that intensity values can be assigned. The results of this postal canvass and information furnished by other sources are used to assign an intensity value, and to compile isoseismal maps that show the extent of various levels of intensity within the felt area. The maximum observed intensity generally occurs near the epicenter. 
Richter
Magnitude 
Mercalli
Intensity 
Description

2

I

Usually not felt, but detected by instruments. 
II

Felt by very few people.  
3

III

Felt by many, often mistaken for a passing vehicle. 
IV

Felt by many indoors, dishes and doors disturbed.  
4

V

Felt by nearly everyone. People awakened. Cracked walls, trees disturbed. 
5

VI

Felt by all. Many run outdoors. Furniture moves. Slight damage occurs. 
VII

Everyone runs outdoors. Poorly built buildings suffer severe damage. Slight damage every where else.  
6

VIII

Everyone runs outdoors. Moderate to major damage. Minor damage to specially designed buildings. Chimneys and walls collapse. 
7

IX

All buildings suffer major damage. Ground cracks, pipes break, foundations shift. 
X

Major damage. Structures destroyed. Ground is badly cracked. Landslides occur.  
8

XI

Almost all structures fall. Bridges wrecked. Very wide cracks in ground. 
XII

Total destruction. Ground surface waves seen. Objects thrown into the air. All construction destroyed. 
Earthquake Energy as a Function of Magnitude  
Magnitude (Richter) 
Energy Equivalent Weight of TNT* 
Energy in joules (1 J = 1 newton meter) 
Notes 
3.0  0.001 ounces  2 J  1.5 foot pounds (18 inch pounds) 
2.0  0.032 ounces  63.1 J  47 foot pounds 
1.0  1.0 ounces  2E+03 J  1,500 foot pounds 
0.0  32 ounces  63.1E+03 J  
1.0  63 pounds  2E+06 J  
2.0  1 ton  63.1E+06 J  Only felt nearby. 
3.0  32 tons  2E+9 J  
4.0  1 kton  63.1E+9 J  Often felt up to 10's of miles away. 
5.0  32 ktons  2E+12 J  
6.0  1,000 ktons  63.1E+12 J  
6.9  22,700 ktons  1.41E+15 J  1995 Kobe, Japan, Earthquake 
7.0  32,000 ktons  2E+15 J  
8.0  1 Mtons  63.1E+15 J  
9.0  32,000 Mtons  2E+18 J  
9.2  64,000 Mtons  3.98E+18 J  1964 Alaska Earthquake  Second largest instrumentally recorded earthquake 
9.5  180,000 Mtons  11.2E+18 J  1960 Chile  Largest instrumentally recorded earthquake 
Precautionary
measures
+
behavior
during earthquakes:
>Publiced by IGN (Instituto Geográfico Nacional
de Espańa)<
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