the worlds first freely available P2P warning
TsunamiHDD has won an award at PrixArs2006
how it works ]
Tusnamis are generated by earthquakes, volcanic eruptions
or large meteorite impacts. These initial events cause seismic
waves which can be sensed by the fragile components of computer
harddisks. Seismic waves travel with about 5000 m/s (18.000
km/h), while tsunamis travel much slower with a speed of 200
m/s (720 km/h, depending on the local depth) through water.
This gives time for a tsunami forecast to be made and warnings
to be issued to threatened areas, if warranted.
The Tsunami Harddisk
Detector is a small software client (see Fig. 1) installed
on your computer which continuously monitors the vibration
of the internal components of your harddisk (see Fig.
2). Since they are extremely fragile, they react to
any accelerations of the computer, including those that
originate from earthquakes. Different technical strategies
are currently under investigation to analze seismic
activity. For best performance, the computer with its
harddisk should be fastened to the ground.
Fig. 1: Mainwindow of the software client application.
Fig. 2: Harddisk read/write head.
One computer is not
enough to identify the epicenter of an earthquake. However,
a small number of networked computers can locate the
epicenter, measure the intensity and estimate the risk
of a tsunami. To this end, the computers are connected
via a P2P network. To organize the
communication within the network, it consists of many
nodes (which perform sensing) and a few supernodes (which
perform signal processing). In particular, the supernodes
perform two tasks:
locate the epicenter based on
the time lag and intensity of the event
remove ‘signal noise’.
Noise is generated by events that shake the harddisk,
but can not cause a tsunami (e.g. a user kicks his
computer). The supernode can detect this noise because
it is improbable that many users kick their computer
In order to be able to locate the epicenter, each node
must know exactly where it stands on earth. Therefore,
the longitude and latitude as well as the orientation
must be entered when the software is started the first
time. This data can be obtained from an attached GPS-mouse
or from www.gpsvisualizer.com.
Fig. 3: P2P network
consisting of nodes used for sensing (white dots)
and supernodes used for data analysis (red dots).
Although the described method works
in principle, it has inherent problems: the internals
of harddisks operate at very high speeds with frequencies
of about 1 kHz, while earthquakes exhibit much smaller
frequencies (see the seismogram to the right). Also
the accelerations during normal harddisk operation are
about 30 g, while an earthquake has a much smaller horizontal
acceleration (for example the Kobe earthquake in 1995
had 0.84 g horizontally). Hence, the waves resulting
from earthquakes must be filtered out from other waves.
Fig. 4: Sample seismogram.
The contents of these pages and provided software are used
at your own risk. We do our best to make the warning system
as reliable as possible. The authors of the site, its algorithms
and data ACCEPT NO LIABILITY UNDER ANY CIRCUMSTANCES FOR ANY
USE OF ANY INFORMATION OBTAINED FROM THIS SITE.