Measured / sourced
Terrain elevation and the listed reference sources anchor the experience. They still carry resolution, age, and coverage limits.
Mayon Rajan is a free educational visualization. It combines measured terrain, a static imagery drape, historical interpretation, and conceptual scientific models. Those are different kinds of evidence and should not be read with the same confidence.
Terrain elevation and the listed reference sources anchor the experience. They still carry resolution, age, and coverage limits.
Story scenes and heritage views condense complex accounts into short learning experiences. They are not complete reconstructions.
Interior volumes and hazard overlays explain processes. They do not claim to be direct images, forecasts, or evacuation maps.
The visible ground is driven by a locally baked 52 km × 52 km elevation grid centered on Mayon. The grid is derived from NASA SRTM elevation via AWS Terrain Tiles and is stored as metre-valued height data in the site package. At runtime, this grid replaces the procedural fallback terrain.
That makes slopes, surrounding plain, and broad relief useful for scale and orientation. It does not make every ridge, road, drainage line, or summit detail survey-grade. The model should not be used for surveying, route planning, property decisions, or safety decisions.
The ground imagery is a locally baked Esri World Imagery mosaic, resampled into the 52 km model area. The site uses it as visual context for settlement, vegetation pattern, and landform—not as a current satellite feed.
Imagery date: there is no single acquisition date for this drape. World Imagery is a composite service whose source imagery can vary by tile and time; the static local bake is not automatically refreshed. Do not infer current land cover, current roads, current lava, ash, weather, or activity from the imagery.
The imagery layer was last baked for this experience on 24 July 2026. A future rebake will be recorded in the public change log.
The transparent chamber, conduit, dike, and hydrothermal forms beneath Mayon are intentionally schematic. Their purpose is to show how volcanologists use indirect observations—erupted material, seismicity, deformation, gases, gravity, and physical models—to reason about a system they cannot directly see.
The model draws on published petrological context suggesting shallow storage on the order of 0–8 km beneath the crater and deeper crystal-rich storage around 18–20 km. It does not claim that those volumes have been imaged with their displayed shapes, sizes, positions, or connections.
Use it to ask “what evidence could support this inference?” Never read it as a map of a known chamber wall, an indication of current magma movement, or a forecast of eruption.
The hazard simulator renders illustrative lava, pyroclastic-density-current, lahar, and ash paths over local terrain. Its broad distance rings and directional context are informed by published PHIVOLCS hazard-map material; the moving paths are visual teaching devices designed to compare processes.
The simulator does not ingest live seismicity, gas, deformation, rainfall, wind, alert levels, eruption rate, vent conditions, or evacuation-zone data. It does not perform numerical flow, inundation, or ash-dispersion modeling. Changing the intensity control changes visual opacity and emphasis—not a probability, volume, or official alert level.
The 2018 night Event Replay is an authored visual reconstruction that combines the site’s historical era layer, animated particles, night lighting, and a staged camera movement. It is not a calibrated replay of a specific photograph or moment, and its glow, fountain height, plume shape, lava extent, and timing are visual choices rather than measured event parameters.
For current Mayon status, warnings, exclusion zones, evacuation instructions, rainfall conditions, or any real-world action, consult PHIVOLCS, local government authorities, and emergency services. This site is never an operational hazard product.
The time control now calculates the Sun’s apparent topocentric position for Mayon’s summit: 13.2567° N, 123.6850° E, 2,463 m elevation (WGS 84). It uses Astronomy Engine 2.1.19, the same ephemeris family documented by Maha’s Celestial Fact Layer. The scene uses Philippine civil time (Asia/Manila, UTC+08:00).
By default, calculations use the current date in Philippine time. A shared link may include ?date=YYYY-MM-DD to reproduce another date. The time slider changes the local civil time on that chosen date; the resulting solar altitude and azimuth drive the rendered sun, light, fog, sky, stars, and plume lighting. Hover or focus the time label to see the calculated sunrise and sunset for the active date.
Sunrise and sunset use Astronomy Engine’s apparent upper-limb horizon event, including its standard near-horizon refraction correction. They are suitable for the educational scene but are not an official operational time service: local terrain obstruction, weather, and real atmospheric conditions can change what an observer sees.
This project does not silently refresh its terrain, imagery, historical interpretation, interior model, or hazard scenarios from a live feed. A change is published when a new data bake, source interpretation, learning guide, or material model revision is released.
Last source-registry review: 24 July 2026. This methodology page was updated 28 August 2026 to make the solar calculation and model boundaries explicit.
Each listed source is linked with its specific role in the visualization. The registry is a reading guide, not a claim that every source validates every visible feature.
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