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How to use this hub
Start with one real question. Pick one category button.
Open one calculator first. Check units and assumptions.
Then move to the next tool only if you need more detail.
Keep your location, date, and units the same across tools.
Use official data and local guidance for final decisions.
Simple start for first-time users
Pick one place on the map and one date first.
Write down your goal in plain words before you start.
Ask one small question at a time and keep the scope narrow.
Use one tool, read the result, then decide the next step.
Do not change many inputs at once in the first run.
Check units each time you copy values between tools.
Keep meters with meters, and keep feet with feet.
Keep local time with local time for all date calculations.
When you compare two cases, change only one input.
Save each run with a short note about what changed.
Use clear names like north-river-rain and west-hill-wind.
If a result looks odd, run the same case again.
Then run one known sample to make sure settings are right.
For hazard topics, treat outputs as rough guidance only.
Use local alerts, maps, and expert advice for real action.
For class use, keep the same setup for all students.
For team use, share links so all members see the same input.
Use short logs: place, date, unit set, and key output.
Review the log at the end and mark the best run.
If needed, export data and keep source links with it.
Small steps work best. Slow is fine. Clear is best.
One tool now. Next tool later. Keep your flow calm.
Check map, sky, rain, and wind before final plans.
Use the same base case when you teach this topic.
Short notes help you spot mistakes fast.
Good logs make team review much easier.
If two tools disagree, check units and time zones.
Then test one clean sample from the help text.
Keep only what you need for the next step.
Clear input leads to clear output.
Filter by keyword
Suggested workflows
Use these short paths when you are not sure where to begin.
- Earthquake basics: Magnitude and energy → Moment magnitude → P-S distance → Tsunami arrival.
- Rain and water: Rainfall to volume → Open channel flow → Nutrient load → DO and BOD/COD.
- Air quality: Gas ppm and mg/m3 → AQI → Stack height → Plume model.
- Sun and horizon: Distance and bearing → Solar position → Horizon distance → Moon and tide.
- Earth interior: Geothermal gradient → Radiometric age.
- Land flow: Slope and grade → USLE erosion → Runoff estimate.
Follow each row from left to right as a suggested learning route.
Recommended tools
- Earthquake Energy Calculator: Magnitude Comparison.
Use this earthquake energy calculator to compare two magnitudes and estimate how much more energy a magnitude 7.
- Distance/azimuth calculator for two latitude.
Calculate the distance and direction (initial/terminal) from the latitude and longitude of two points.
- Solar altitude/azimuth/sunrise/sunset/day length.
Approximate solar altitude, solar direction, sunrise/sunset, day length, and solar meridian from latitude/longitude.
- Rainfall to Volume and Flow Rate Converter.
Convert rainfall (mm) and area into water volume (m³).
- ppm/ppb ↔ mg/m³ conversion (gas).
ppm/ppb (volume mixing ratio) and mg/m³ (mass concentration) are calculated mutually by specifying temperature.
- Calculate epicenter distance and occurrence time from P.
The epicenter distance is roughly estimated from the arrival time difference between P waves and S waves (S-P).
- AQI (Air Quality Index) Calculator (US EPA).
Convert 24-hour PM2.5 and PM10 concentrations (µg/m³) to US EPA AQI. Check category, breakpoints, truncation.
Disaster Preparedness (Earthquake, Tsunami, Ground)
Learning and estimation tools for earthquakes, tsunamis, and ground response.
- Earthquake magnitude and energy comparison calculator
Calculate the released energy ratio from two earthquake magnitudes.Tags: Earthquake / Magnitude / Energy / Education / Category: Disaster Preparedness (Earthquake, Tsunami, Ground)
- Epicenter distance and event-time estimator from P-S waves
Estimate epicenter distance from the S-P time gap and review the basic arrival-time method.Tags: Earthquake / P wave / S wave / Epicenter distance / Category: Disaster Preparedness (Earthquake, Tsunami, Ground)
- Tsunami speed and arrival time calculator
Estimate tsunami speed and arrival time from average water depth and travel distance.Tags: Tsunami / Arrival time / Shallow-water wave / Education / Category: Disaster Preparedness (Earthquake, Tsunami, Ground)
- Moment magnitude Mw calculation (fault→M0→Mw)
Calculate seismic moment M0 and Mw from fault parameters.Tags: Earthquake / Mw / Moment / Fault / Category: Disaster Preparedness (Earthquake, Tsunami, Ground)
- Earthquake catalog b-value estimator
Create an FMD from catalog data and estimate Gutenberg-Richter b and a values.Tags: Earthquake / b value / Gutenberg-Richter / Research / Category: Disaster Preparedness (Earthquake, Tsunami, Ground)
- Liquefaction risk indicator (education)
Screen liquefaction risk using shaking intensity, groundwater level, and soil conditions.Tags: Liquefaction / Ground / Earthquake / Education / Category: Disaster Preparedness (Earthquake, Tsunami, Ground)
Mapping and Terrain (Geodesy, Slope, Curvature)
Core map and terrain calculations, including geodesic distance and bearing, slope metrics, and horizon curvature.
- Distance/azimuth calculator for two latitude-longitude points
Calculate geodesic distance and initial/final bearing between two coordinates.Tags: Geodesy / Distance / Bearing / Mapping / Category: Mapping and Terrain (Geodesy, Slope, Curvature)
- Slope and angle calculator
Calculate slope (%/‰), angle (°), and slope distance from horizontal.Tags: Gradient / Slope / Elevation difference / Terrain / Category: Mapping and Terrain (Geodesy, Slope, Curvature)
- Horizon distance and Earth curvature drop calculator
Approximate horizon distance and curvature drop from observation altitude.Tags: Earth curvature / Horizon / Refraction coefficient / Visibility / Category: Mapping and Terrain (Geodesy, Slope, Curvature)
Atmosphere and Weather (Sun, Humidity, Air Quality)
Practical atmospheric calculations for solar position, pressure-altitude conversion, humidity metrics, gas concentration, and AQI.
- Solar altitude, azimuth, sunrise, sunset, and day length
Approximate solar position and daylight timing from coordinates, date, and time.Tags: Sun / Sunrise / Sunset / Daylight / Category: Atmosphere and Weather (Sun, Humidity, Air Quality)
- Pressure-altitude conversion (standard atmosphere)
Convert atmospheric pressure and altitude with ISA and sea-level correction options.Tags: Atmospheric pressure / Altitude / Standard atmosphere / Conversion / Category: Atmosphere and Weather (Sun, Humidity, Air Quality)
- ppm/ppb ↔ mg/m³ conversion (gas)
Specify temperature, pressure, and molecular weight to convert ppm/ppb and mg/m³.Tags: ppm / mg/m³ / Conversion / Gas / Category: Atmosphere and Weather (Sun, Humidity, Air Quality)
- Dew point, wet-bulb, and heat-index calculator
Calculate dew point, wet-bulb temperature, and heat index from weather inputs.Tags: Dew point / Wet bulb / Heat index / Weather / Category: Atmosphere and Weather (Sun, Humidity, Air Quality)
- AQI (Air Quality Index) Calculator (US EPA)
Calculate US EPA AQI from PM2.5 and PM10 concentrations and show categories and breakpoints.Tags: AQI / PM2.5 / PM10 / Health guidance / Category: Atmosphere and Weather (Sun, Humidity, Air Quality)
- Tide/moon phase/sunrise/sunset calculation
Show sunrise/sunset, moon phase, and tide values from shared or manual inputs.Tags: Tides / Moon phase / Sunrise / Ocean / Category: Atmosphere and Weather (Sun, Humidity, Air Quality)
Water (Rainfall, Flow, Water Quality)
Tools for rainfall-to-runoff estimates, open-channel flow, nutrient load, and water-quality checks.
- Rainfall to volume and flow conversion
Convert rainfall depth and area into runoff volume and flow estimates.Tags: Rainfall / Flow rate / Runoff / Hydrology / Category: Water (Rainfall, Flow, Water Quality)
- Nutrient load calculation
Calculate the total load (kg) from concentration x flow rate x time.Tags: Water quality / Nutrients / Load amount / Conversion / Category: Water (Rainfall, Flow, Water Quality)
- Open-channel flow calculator (Manning method)
Approximate flow velocity V and flow rate Q using Manning's formula.Tags: Open channel / Manning / Flow rate / Hydraulics / Category: Water (Rainfall, Flow, Water Quality)
- DO saturation, BOD/COD load, and removal calculator
Calculate DO saturation and saturation ratio from water temperature, then estimate BOD/COD load and removal.Tags: Water quality / DO / BOD / COD / Category: Water (Rainfall, Flow, Water Quality)
Environmental Engineering (Dispersion, Stack, Noise, CO2)
Environmental engineering estimators for plume dispersion, stack rise, noise, and electricity-related CO2 emissions.
- Noise calculation (dB addition/distance attenuation)
Approximate combined noise level (dB) from multiple sources and distance attenuation.Tags: Noise / dB / Distance attenuation / Source combination / Category: Environmental Engineering (Dispersion, Stack, Noise, CO2)
- Gaussian plume dispersion calculator
Estimate concentration C(x, y, z) with a Gaussian plume model for point sources.Tags: Dispersion / Gaussian plume / Atmosphere / Education / Category: Environmental Engineering (Dispersion, Stack, Noise, CO2)
- Electricity CO2 emissions calculator (kWh to kg-CO2)
Estimate CO₂ emissions from electricity consumption and emission factors.Tags: CO2 / Electricity / Emission factor / Conversion / Category: Environmental Engineering (Dispersion, Stack, Noise, CO2)
- Effective stack height calculator
Approximate plume rise and effective chimney height using Briggs formula.Tags: Stack / Plume rise / Dispersion / Briggs / Category: Environmental Engineering (Dispersion, Stack, Noise, CO2)
Earth Interior and Age (Geothermal, Radioactivity)
Core calculations for geothermal gradient, heat flow, and radioactive decay dating.
- Radioactive decay dating calculator (half-life/ratio)
Calculate the age from the half-life and survival rate (N/N0).Tags: Half-life / Dating / Radioactivity / Exponential decay / Category: Earth Interior and Age (Geothermal, Radioactivity)
- Geothermal gradient/heat flow
Calculate geothermal gradient dT/dz from temperatures at two depths and estimate heat flow.Tags: Geothermal / Gradient / Heat flow / Conduction / Category: Earth Interior and Age (Geothermal, Radioactivity)
Soil and Land (Erosion)
Simple erosion estimation based on USLE/RUSLE factors.
- USLE/RUSLE soil erosion calculator (simple)
Simple estimate of soil runoff amount using A=R×K×LS×C×P of USLE/RUSLE.Tags: Soil / Erosion / USLE / RUSLE / Category: Soil and Land (Erosion)
What is geology/environment?
Geology and environment is a field that uses numerical values to understand natural phenomena and people's lives, crossing fields such as earthquakes, tsunamis, topography, weather, water quality, and environmental engineering. In this hub, you can check calculations that can be used for learning, reports, and initial confirmation on-site in the flow of input → results → procedures.
*The tools in this guide are for learning estimates. Confirm design, safety, compliance, and reporting decisions with official standards and professional review.
Choose the earth-science page by the field task
Use this hub when the problem is environmental or geoscience, but you still need to choose the right calculator. The fastest route is to decide whether the job is hazard timing, air and water quality, terrain and runoff, or field conversions.
Where to go first
- Hazards: earthquake, tsunami, liquefaction, and event-timing checks
- Air and water: plume, AQI, water-quality, and load-style environmental calculations
- Terrain and runoff: slope, rainfall-runoff, soil loss, and site-estimate tools
- Field conversions: distance, bearing, and environment-facing unit conversions
Before you compare outputs
Keep units, time basis, and observation conditions aligned. Most surprising differences come from changing those assumptions without noticing.
FAQ
Which tool should I start with?
The quickest way is to start with purpose-specific shortcuts. For example, you can follow the steps in the necessary order, such as "rainfall → flow rate → load → water quality."
Can the calculation results be used directly for practical decisions?
No. The calculations here are for educational and approximate purposes; in practice, professional judgment is required, including observation conditions, laws and regulations, and design standards.
What does the shared URL contain?
The shared URL includes input conditions and display settings. It is not intended to be used to input personal information.
When should I leave this hub for another science section?
Leave this hub when the task becomes chemistry-heavy lab work, astronomy planning, or pure physics formulas. Stay here when the context is environmental, geologic, or field-observation based.
Related hubs
- Chemistry hubMove here when the next step is pH, concentration, solution prep, or reaction chemistry.
- Biology hubSwitch here when the interpretation turns into growth, ecology, or assay-oriented biology work.
- Science & engineering hubReturn here if you need to step back and choose a different science family.