For this post, I
am relying on Smart Solo Scientific’s July 2024 post: Seismometer
vs. Geophone: A Guide to Seismic Sensing Tools, as
well as a webinar presented by Sercel/Accel. There are two main types of
seismic sensors: geophones and seismometers. A seismic sensor is a device that
detects and measures ground vibrations. The vibrations, also known as seismic
waves, can detect a multitude of ground vibrations from earthquakes to mine
blasting. They need a sound source, typically a blast of dynamite or a
vibration truck.
Geophones
Geophones are most common in
the field, being the standard seismic sensor for geophysical exploration.
“The basic principle is simple but effective: inside a
geophone, a suspended mass (usually a coil of wire) moves relative to a magnet
as the ground shakes. This movement generates a small electrical voltage that
is directly proportional to the velocity of the ground motion.”
“Because they are relatively simple, durable, and
cost-effective, geophones are perfect for deploying in large numbers for
seismic surveys hunting for oil, gas, and minerals.”
Seismometers
In contrast, a seismometer
contains a geophone for detecting and measuring ground motion, but integrates
it into a system of analysis. Smart Solo defines a seismometer as:
“…a sophisticated, integrated system designed for
detailed seismic analysis. At its heart, a seismometer typically contains a
highly sensitive geophone – the component that actually detects ground motion.
However, a seismometer is much more than just the geophone itself. It’s a
complete instrument package that includes advanced electronics for signal
processing, precise timing (often via GPS), data storage, and communication
capabilities.”
The term seismometer can also
refer to enhanced methods utilized in geophysical exploration that go beyond
mere sensing and become comprehensive data acquisition systems.
Nodes: No More Heavy Cables Means Faster, Cheaper Surveying
with Better Signal Quality
In the past, conducting large
seismic surveys involved physically laying out massive amounts of heavy cables
that connected the signals together. Now, signals can be detected and measured
wirelessly by what are called nodes. This represents a revolution in seismic
since it leads to faster, cheaper surveying, not limited by rough terrain.
Nodes have also demonstrated better signal quality. Rivers, mountains, and
dense forests are no longer impediments to seismic surveys.
“A seismic node represents a significant evolution in
seismic instrumentation, essentially an advanced, self-contained form of
seismometer. It ingeniously combines all essential components – a sensitive
geophone for motion detection, an integrated battery for power, GPS for precise
timing and location, and onboard data storage – into a single, compact, and
autonomous unit.”
“Crews can now deploy thousands of nodes quickly and
easily, by hand or even by drone, across almost any terrains. This has opened
the door to ultra-dense surveys that produce incredibly high-resolution images
of the Earth’s subsurface, something that was previously unimaginable.”
Smart Solo has a 2D node version, the IGU-16, and a 3-component (3C) smart seismic sensor, the IGU-16HR 3C, that collects data in three dimensions for a 3D seismic survey.
The company
can also pair the nodes with its data logger, a 3-Channel Intelligent
Monitoring Unit, the IMU-3C, described below.
Smart Solo also notes that
the massive data sets provided by nodal seismology are very amenable to machine
learning methods of analysis.
“The future of seismic exploration and monitoring is all
about data—more of it, and better quality. The massive datasets generated by
large-N (large number) nodal surveys are perfect for feeding into AI and
machine learning algorithms. These advanced tools can help automate the process
of picking seismic arrivals, filtering out noise, and even identifying patterns
that could predict geological hazards.”
Company Sercel sells what it calls its Accel drop nodes, nodes that can simply be dropped into place, with spikes to hold them in place or not. These are hand-sized.
The company says its
nodes can save about 30% in opex. Fewer personnel are needed in the field for
deployment and retrieval. Testing has confirmed that its drop nodes have signal
quality as good as buried or spiked nodes. The company also claims that its
drop nodes can be less affected by noise from wind and rain than buried or
spiked nodes. Its nodes are integrated into its QuietSies and Pathfinder data
technologies. The EU-based company is currently testing and deploying its nodes
in Texas, among other places.
References:
Seismometer
vs. Geophone: A Guide to Seismic Sensing Tools. July 4, 2025. Seismometer vs. Geophone: A Guide to Seismic
Sensing Tools - SmartSolo
Accel:
Accelerate your operations. Sercel. Accel | Sercel
Discover
Accel, the world's first drop node. Accel/Sercel. Webinar. November 20, 2025.
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