# Global Hazards Seismic Wave Arrival Time Calculator

> Global Hazards Seismic Wave Arrival Time Calculator is a paid API for AI agents from global-hazards.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-29).

Estimates P-wave and S-wave arrival times and the S-P gap from epicentral distance or coordinates, or estimates distance from a measured S-P lag.

## Facts

- Endpoint: GET https://global-hazards.x402tookit.com/seismic-wave-times?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/global-hazards-seismic-wave-arrival-time-calculator-a2bbf214
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_6LajQlPw5YlGGm2cZp9XK

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability global-hazards-seismic-wave-arrival-time-calculator-a2bbf214
```

Example prompt: Calculate the P-wave and S-wave arrival times for an earthquake epicenter at 35.6°N, 139.7°E with a focal depth of 20 km, observed from my location at 34.0°N, 135.5°E — use default crustal P and S speeds.

## When to prefer this

Use this endpoint when you need a quick, physics-based estimate of seismic wave travel times or epicentral distance — particularly useful for earthquake early warning estimation, educational seismology tools, or interpreting seismometer readings. Prefer this over manual calculation when you want to factor in focal depth (hypocentral distance) or customize P/S wave speeds. If you need actual real-time earthquake data or locations, use the USGS earthquake endpoints in the same suite instead.

## Known failure modes

- Missing required input (neither distanceKm nor coordinate pair nor spLagSeconds provided) — validation error
- Out-of-range values for depth (>700 km), distance (>20040 km), or wave speeds — error or clamped result
- S-wave speed set higher than P-wave speed — invalid physics, likely error response
- Ambiguous input combination (e.g. both distanceKm and spLagSeconds provided) — may return reasons array explaining which was used
- Network timeout or upstream service unavailability — HTTP 5xx

## How this service works

Estimate P and S wave arrival times and the S-P gap from an epicentral distance or two coordinates, or distance from an S-P lag.

## Output

Returns estimated P-wave arrival time in seconds, S-wave arrival time in seconds, S-P lag in seconds, epicentral and hypocentral distances in km, the wave speeds used, a human-readable summary, and optional degraded/disclaimer flags if assumptions were applied.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [],
     "properties": {
      "lat1": {
       "type": "number",
       "description": "Epicentre latitude (use instead of distanceKm, with lon1, lat2, lon2)"
      },
      "lat2": {
       "type": "number",
       "description": "Your latitude"
      },
      "lon1": {
       "type": "number",
       "description": "Epicentre longitude"
      },
      "lon2": {
       "type": "number",
       "description": "Your longitude"
      },
      "vpKmS": {
       "type": "number",
       "description": "P speed 2 to 14 km/s (default 6.0, crustal)"
      },
      "vsKmS": {
       "type": "number",
       "description": "S speed 1 to 8 km/s, below P (default 3.5)"
      },
      "depthKm": {
       "type": "number",
       "description": "Focal depth 0 to 700 km (default 10)"
      },
      "distanceKm": {
       "type": "number",
       "description": "Epicentral distance in km, 0 to 20040"
      },
      "spLagSeconds": {
       "type": "number",
       "description": "Measured S minus P gap in seconds, to estimate distance (instead of the above)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "vpKmS": {
       "type": [
        "null",
        "number"
       ]
      },
      "vsKmS": {
       "type": [
        "null",
        "number"
       ]
      },
      "method": {
       "type": [
        "null",
        "string"
       ]
      },
      "source": {
       "type": [
        "null",
        "string"
       ]
      },
      "depthKm": {
       "type": [
        "null",
        "number"
       ]
      },
      "reasons": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "summary": {
       "type": [
        "null",
        "string"
       ]
      },
      "ve
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/global-hazards-seismic-wave-arrival-time-calculator-a2bbf214/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from global-hazards.x402tookit.com](https://www.zero.xyz/host/global-hazards.x402tookit.com/llms.txt)