Tag Archives: earthquake

Student Seismology Research Station – Seismometer and Magnetometer Recording Via Computer Sound Card

(Seismology = the study of earthquakes
Seismometer = device for measuring earthquakes
Magnetometer = device for measuring magnetic fields)

One cannot ordinarily record earthquakes via a computer sound card as they don’t respond much to the slow vibrations experienced in earthquakes. (Update: not strictly true. See my latest on this: Simplest Seismometer – Experiments with direct recording through PC sound card) However, with some cheap electronic trickery and clever software, it can be done, and very adequately for the purposes of study. The seismometer above, made by a high school student, in its first night of testing recorded this local 3.8 quake – a magnitude 1 in Taipei:

(click on the pictures for larger versions)

and as a surprise bonus, some filtering of background noise revealed this distant quake as well. It was a 5.9 from 1000 km away in the Philippines.

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Can earthquakes be predicted? A simple magnetometer for detecting earthquake precursors

magnetometer: n. [Magneto- + -meter]
An instrument for measuring the intensity of magnetic forces [1913 Webster]

precursor:  One who, or that which, precedes an event, and indicates its
approach; a forerunner [1913 Webster]

Scientists, particularly in Japan, have for many years been gathering evidence of electromagnetic signals that come from under the ground before earthquakes. The bigger the signal, the bigger the quake is likely to be. This can occur hours before, and in some cases, days or even weeks before the quake itself. Why it happens is not well understood but current theory is that it has to do with rocks creating large electric currents as a result of crushing or grinding under high pressure. Several methods have been used to detect these reportedly erratic, electromagnetic pulses. The method described here is one of the simplest. Technically, it’s called a “search coil magnetometer.” This does not respond to very slow magnetic changes, but it can sense short-term ones, making it suitable for detecting earthquake precursors. Continue reading

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Recording Earthquakes for Beginners – The Background Story

Background

In my search for educational projects that can engage a kid’s interest, I recently began looking into seismology (from Ancient Greek, “seismos”, an earthquake and “logia”, study of.)

Being a rather high-tech subject, I was skeptical of my chances of reducing it to something kids could do, but I gave it a shot anyway, since it’s very applicable here in Taiwan, where earthquakes average a couple a day. (You can see them on this website: http://www.cwb.gov.tw/eng/index.htm )

The goal was to come up with some kind of a detector; the simplest and cheapest design possible that a student could plug into a computer and record real earthquakes. Although still in progress I wanted to share what I’ve done so far as it’s a fascinating field and full of good, observable data that will give anyone a deeper understanding of the planet we live on. Continue reading

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