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In this section, it is hoped to put ideas for using seismology and the associated skills we are using to help children in classroom situations.  Below is a start from Sue Kominek at Gundaroo Primary School,  southern NSW

”Last year we printed off all the earthquakes around the world above 5, in a week or month. The kids then joined the pages together and counted them all, then calculated how many high magnitude earthquakes we'd possibly have in a week, month, year, etc, over magnitude 5. Different kids highlighted earthquakes from different areas, identified the plates and fault lines, etc. They could also identify an earthquake on our readings! Not bad for 8 - 10 year olds!

Sue”
 

Q. I want to monitor earthquakes, what kind of seismometer do I need ?

 A. This depends on what you want to do. You see a range of seismic signals depending on the distance from the quake to your sensor. The higher frequency signals are absorbed as they travel through the earth. Local quakes can generate fast P waves up to 10 Hz. Near Regional quakes up to 5 Hz, far Regional quakes up to about 3 Hz and teleseismic quakes up to about 2 Hz. The S waves which follow them are usually at about 1/2 of the P wave frequency. When these waves strike the surface of the earth, they generate much slower surface transverse Love waves and vertical Rayleigh waves with periods typically of 15 to 25 seconds, but you sometines see additional waves at about 40 seconds, or at even longer periods from the occasional great quakes. You also see environmental noise and microseism ocean background noise, usually at about 5 to 6 seconds period ~ 2 Hz.

Q. What do seismometers measure ?

A. Seismometers measure ground motion within the bandwidth of the instrument and output a voltage proportional to either ground displacement, velocity or acceleration depending on the frequency of the ground motion relative to the natural frequency of the seismometer.

Accelerometers act as insensitive seismometers but are usually force-balance instruments, the output voltage proportional to ground acceleration up to the corner frequency of the accelerometer.

 

The Modified Mercalli Intensity Scale

Various scales for measuring the degree of earthquake disturbance have been designed by various people and agencies over the centuries of human civilisation. The scale in most general use at present is called the Modified Mercalli Scale, and has a maximum intensity rating of 12. Maps relating the felt intensity effects of earthquakes are called Isoseismal maps, and contour regions having the same value on the Modified Mercalli Scale. This scale is summarised below


THE MODIFED MERCALLI INTENSITY SCALE

MM I Not felt by humans, except in especially favourable circumstances, but birds and animals may be disturbed. Reported mainly from the upper floors of buildings more than 10 storys high. etc

MM II Felt by a few persons at rest indoors

MM III Felt indoors, but not identified as an earthquake by everyone.

MM IV Generally noticed indoors, but not outside

MM V Generally felt outside, and by almost everyone indoors. Most sleepers awakened. A few people frightened

MM VI Felt by all. People and animals alarmed. Many run outside. Difficulty experienced in walking steadily

MM VII General alarm. Difficulty experienced in standing. Noticed by drivers of motor cars. Trees and bushes strongly shaken.

MM VIII Alarm may approach panic. Steering of moror cars affected

MM IX General panic

MM X Most masonry structures destroyed

MM XI Wooden frame structures destroyed

MM XII Damage virtually total

classroom

            Australian Seismometers in Schools

 is a four-year project(2011-2014) funded by the Geophysical Education Observatory component of AuScope Australian Geophysical Observing System (AGOS) funded by the DIISRTE, under the Education Infrastructure Scheme. The seismometer network will be complemented by an educational website allowing real time access by students to earthquake recordings from both local and global earthquakes. The portal will be designed to align with Australian educational syllabi at multiple teaching levels.

 

IRIS E&O program

one-page handouts related to seismology

for use in the classroom or public information forums.

Teaching Links

Earthquake basics   Geoscience Australia

 

A series of lectures on seismology

 by Nick Rawlinson

Research School of Earth Sciences 
Australian National University 

 

Reference library

A wealth of information including exercises of earthquake magnitude determination and location, highly recommended

 

 
 

accretionary_wedge

subduction

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