地楽

CHIRAKU is an educational simulation app that allows users to interactively learn about major phenomena in earth science.

It is ideal for supporting learning in earth science, science, and planetary science at the middle school, high school, and first-year university levels. Each simulation progresses in four phases: "Initial State → Formation → Development → Final Form," and finally reaches real-world topography or representative observation examples, allowing learners to intuitively understand "what is happening" and "what the end result is."

[Included Simulations]

1. Plate Movement
Visualizes the development of three types of plate boundaries—divergent, convergent, and transform—over time. Each ultimately reaches characteristic topography such as the "Mid-Atlantic Ridge," "Japan Trench/Japanese Archipelago," and "San Andreas Fault."

2. Seismic Wave Propagation
Shows the time progression of P-waves and S-waves radiated from the epicenter propagating through the earth and reaching three observation points to form seismograph waveforms.

3. Epicenter Determination
Learn the mechanism of triangulation, where the distance to the epicenter is calculated using the Omori formula from the time difference of PS measurements taken at three observation points, and the epicenter is identified at the intersection of three circles.

4. Volcanic Eruption
Experience how eruption styles change depending on the viscosity and gas content of magma in four phases. It progresses from Hawaiian-style lava fountains to Plinian-style giant plumes of smoke.

5. Lava Flow
Visualize how lava flowing down from a mountaintop cools and meanders along the terrain. See the relationship that lower viscosity allows lava to reach greater distances.

6. Earth's Internal Structure
Learn about the four-layer structure of the Earth's crust, mantle, outer core, and inner core, and how seismic waves propagate while refracting and reflecting at the boundaries. Learn about the phenomenon where S-waves stop in the liquid outer core, creating a "shadow zone," which is evidence that the outer core is liquid.

7. Geomagnetism
Observe the Earth's dipole magnetic field, the magnetosphere's protection from solar wind, and the long-term geomagnetic reversal (Chibanian period) in four phases.

[Features]

- All simulations progress in four phases, constantly showing "what is happening."
- Japanese labels for each element (plates, mantle, trenches, faults, earthquake sources, magnetosphere, etc.)
- Physics formulas and explanation sheets (Omori formula, Green's law, Snell's law, etc.)
- Progression speed slider (0.5x to 3x), manual phase transition with ◀ ▶
- Automatic dark/light theme switching
- Japanese and English support
- Compatible with both smartphones and tablets
- Offline operation (connection only when displaying advertisements)

Please use this for school science classes, supplementary materials for cram schools, and home study.