SEGY/SEGD Explorer · Support

SEGY/SEGD Explorer — Support

Last updated: 26 October 2026

Help and technical support for the free seismic data viewer for iOS.

Support e-mail: seismicprocess@gmail.com
Developer: Artur Avtukhov (LinkedIn)
Platforms: iOS 15 or later (iPhone and iPad); Android 5.1 or later; also runs as a web page in a modern browser
Price: Free — no account, no subscription, no in-app purchases
Privacy: Privacy Policy — files stay on your device

What the application does

SEGY/SEGD Explorer opens seismic data files from your device and shows them as a gather or stack section with pan and pinch zoom, variable density, wiggle and combined displays, palettes, display gain, AGC and bandpass. You can read the textual, binary and trace headers, view the amplitude spectrum and, for post-stack 3D SEG-Y volumes, rotate a decimated 3D cube and page through inline, crossline and time slices. Everything is computed on the device.

Supported file formats

SEG-Y revisions 0, 1 and 2 — IBM float, IEEE float, 8/16/32-bit integer and 24/64-bit sample formats, big- or little-endian, extended textual headers. File extensions .segy, .sgy, .seg, .gsy.
SEG-D demultiplexed field records, revisions up to 3.x, including storage-unit labels (SEG-D 3). File extensions .segd, .sgd, .gsd.
Fairfield RG16 (ZLand / Z nodal receiver) files. File extension .rg16.

The 3D cube view needs a post-stack 3D SEG-Y file with inline and crossline numbers in the trace headers (bytes 189 and 193 by default; changeable in the Bytes sheet). Other formats (SU, RSF, SEG-2, SEG-B, proprietary vendor formats) are not supported.

How to open a seismic file

Copy the file to your device — into the Files app (iCloud Drive or "On My iPhone"), to a folder shared by another app, or to Android storage.
Open SEGY/SEGD Explorer and tap Open seismic file (or 3D stack cube view for a post-stack 3D SEG-Y volume).
Pick the file in the system file picker. Large files open in well under a second because traces are read on demand.
Pan with one finger, pinch to zoom the time and trace axes, double-tap to fit. Tap a trace to see its headers; use the toolbar for headers, spectrum, palette, AGC and bandpass.

Troubleshooting

The file is not recognised or the picture looks wrong. Open Display settings → Reinterpret and choose the format (SEG-Y / SEG-D) and byte order explicitly; the automatic detection uses the file extension and the first bytes of the file, which some exports leave inconsistent. Check in the headers sheet that the sample format and sample count match what you expect.
"3D cube view needs a post-stack SEG-Y file". The cube is built from inline/crossline header numbers of a stacked volume; SEG-D field records and pre-stack gathers cannot be shown as a cube.
Only part of a large SEG-D or variable-length SEG-Y file is shown. These layouts are parsed from the first 300 MiB held in memory; a warning tells you when the file is longer. Fixed-layout SEG-Y and demultiplexed SEG-D of any size are read on demand without this limit.
The app closes while building a 3D cube. The device ran out of memory. Close other apps, or try a smaller volume; the cube is decimated to a phone-sized grid but the file is still read once completely.
Settings are not remembered. The app keeps display preferences in its local storage; a browser in private mode or a restricted web view does not allow that. Nothing else is affected.
The file picker does not show my file. Make sure the file has one of the supported extensions listed above; the picker filters on them.

FAQ

How do I open a SEG-Y file?

Tap Open seismic file and pick a .sgy / .segy file. Revisions 0–2 with IBM, IEEE and integer samples are read automatically; if the display looks wrong, set the format and byte order in Display settings → Reinterpret.

How do I open a SEG-D file?

Tap Open seismic file and pick a .segd / .sgd file. Demultiplexed SEG-D records (revisions up to 3.x) are indexed first — a progress bar shows the indexing — and then read on demand. Channel sets, general headers and trace headers are shown in the headers sheet.

Is Fairfield RG16 supported?

Yes. Files with the .rg16 extension (Fairfield ZLand nodal receivers) are read through the same inspector; they are parsed from the first 300 MiB of the file.

Why is my file not recognized?

Usually because the extension is unsupported or the first bytes do not match the expected format (for example a SEG-Y file exported without a textual header, or a SEG-D file with a non-standard revision code). Rename the file to a supported extension and use Reinterpret to set the format explicitly. If it still fails, see "How do I report a problem?".

Does the app upload seismic data?

No. The application makes no network requests at all. Files are read directly from your device and are never sent to the developer or to any third party. See the Privacy Policy.

Do I need an account?

No. There is no registration, no login and no sign-in of any kind.

Is the application free?

Yes. It is free to download and use, without subscriptions, in-app purchases or advertisements.

How do I report a problem?

E-mail seismicprocess@gmail.com with the subject "SEGY/SEGD Explorer bug report" and include:

your iOS (or Android) version;
the app version (shown in the App Store listing or your device's app settings);
the device model;
the seismic file format (SEG-Y revision, SEG-D revision or RG16), its size and, if possible, the sample format and byte order from the headers sheet;
what you did, what you expected and what happened instead; a screenshot helps.

Please do not attach confidential seismic files. If a file is needed to reproduce the problem, we will ask first and suggest sending only the first few megabytes or a synthetic file with the same layout.