{"uid":"cap_6LajQlPw5YlGGm2cZp9XK","slug":"global-hazards-seismic-wave-arrival-time-calculator-a2bbf214","name":"Global Hazards Seismic Wave Arrival Time Calculator","description":"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.","url":"https://global-hazards.x402tookit.com/seismic-wave-times?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"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"]},"verdict":{"type":["null","string"]},"degraded":{"type":["boolean","null"]},"disclaimer":{"type":["null","string"]},"notChecked":{"type":["array","null"],"items":{"type":"string"}},"spLagSeconds":{"type":["null","number"]},"pArrivalSeconds":{"type":["null","number"]},"sArrivalSeconds":{"type":["null","number"]},"epicentralDistanceKm":{"type":["null","number"]},"hypocentralDistanceKm":{"type":["null","number"]}}}}}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.02","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.02/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.02","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.02","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_VZXHIXISdeHyVO7rXp__l","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.02","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"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.","exampleAgentPrompt":"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.","exampleUseCases":[{"title":"Earthquake early warning timing estimate","prompt":"There's been an earthquake with epicenter at 37.8°N, 122.4°W and focal depth of 15 km. I'm at 34.05°N, 118.24°W — how many seconds do I have before the P-wave and S-wave reach me, and what's the S-P gap?"},{"title":"Estimating distance from recorded S-P lag","prompt":"I recorded a 42-second gap between the P-wave and S-wave arrival at my seismometer. Can you use that S-P lag to estimate how far away the earthquake epicenter was, assuming standard crustal wave speeds?"},{"title":"Custom wave speed scenario for deep earthquake","prompt":"Compute P and S wave arrival times for an epicentral distance of 800 km, focal depth of 250 km, using a P speed of 8.1 km/s and S speed of 4.5 km/s — what are the arrivals and hypocentral distance?"}],"resultDescription":"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.","failureModes":["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"],"whenToPreferThis":"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.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-29T13:08:13.357Z","isFirstParty":false,"canonicalSlug":"global-hazards-seismic-wave-arrival-time-calculator-a2bbf214"}