CHIRAKU

CHIRAKU is an interactive educational app for learning the major phenomena of earth science.

Each simulation runs through four discrete phases — initial state, formation, development, and final form — ending at a real-world geological feature or representative observation. This makes it immediately clear what is happening and what the end state looks like, which is essential for classroom and self-study use.

Included simulations:

1. Plate Tectonics
Three types of plate boundaries (divergent, convergent, transform) develop step by step. Each ends at a real-world landform: the Mid-Atlantic Ridge, the Japan Trench and island arc, and the San Andreas Fault.

2. Seismic Waves
P-waves and S-waves radiate from the hypocenter through the crust. Three stations record the arrivals and a seismogram trace builds up at the bottom of the screen.

3. Epicenter Location
The Omori formula turns the P-S time difference into a hypocentral distance. Three circles, one per station, intersect at the epicenter — classic triangulation, visualized.

4. Volcanic Eruption
Magma viscosity and gas content drive four eruption styles in succession: Hawaiian, Strombolian, Vulcanian, and Plinian. Particles, ash, and plumes change accordingly.

5. Lava Flow
A lava channel descends from the crater, meandering down terrain. Cooled segments turn black behind the glowing front. Lower viscosity carries lava farther — observe the runout distance.

6. Earth Interior
Four concentric layers — crust, mantle, outer core, inner core. P-waves penetrate everywhere; S-waves stop at the liquid outer core, creating the shadow zone that proves the outer core is liquid.

7. Geomagnetism
Earth's dipole field, the magnetosphere that deflects the solar wind, and the long-term geomagnetic reversal recorded in the Chibanian-age strata.

Features:

- Four-phase progression with always-visible status header
- Japanese labels on every visual element (plate, mantle, trench, fault, hypocenter, magnetosphere, and more)
- Physics formula sheets (Omori's formula, Green's law, Snell's law, and others)
- Speed slider (0.5x to 3x) and previous/next phase buttons
- Light and dark themes
- Japanese and English supported
- Phone and tablet support

Suitable for science teachers, supplementary classroom use, and independent learners curious about the Earth.