> ## Documentation Index
> Fetch the complete documentation index at: https://docs.terraquakeapi.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Data Sources

> Understanding TerraQuake API data sources, coverage, and reliability

## Primary Data Source

TerraQuake API uses **INGV (Istituto Nazionale di Geofisica e Vulcanologia)** as its primary source for seismic data. INGV is Italy's authoritative institution for geophysics and volcanology research, providing real-time earthquake monitoring and analysis.

> **[INGV](http://terremoti.ingv.it/)**
>
> Official earthquake monitoring service from Italy's National Institute of Geophysics and Volcanology

## Data Format

All earthquake data is provided in **GeoJSON format**, which is a widely-used standard for encoding geographic data structures.

```json Example GeoJSON Structure theme={null}
{
  "type": "Feature",
  "properties": {
    "eventId": 44278572,
    "originId": 140102761,
    "time": "2025-09-26T19:33:46.440000",
    "author": "SURVEY-INGV",
    "magType": "ML",
    "mag": 1.0,
    "type": "earthquake",
    "place": "Costa Calabra sud-orientale (Reggio di Calabria)",
    "version": 100
  },
  "geometry": {
    "type": "Point",
    "coordinates": [16.2387, 37.9982, 10.5]
  }
}
```

The `coordinates` array follows the format: `[longitude, latitude, depth_in_km]`.

## Data Coverage

### Geographic Coverage

While TerraQuake API primarily focuses on **Italian seismic events**, the INGV data source includes:

* **Primary**: All Italian regions and territories
* **Extended**: Mediterranean region
* **Additional**: Significant global seismic events detected by INGV sensors

### Temporal Coverage

The API provides access to:

* **Real-time data**: Current year earthquakes updated continuously
* **Historical data**: Access to past seismic events through date range queries
* **Today's events**: Dedicated endpoint for same-day earthquakes
* **Recent events**: Last 7 days, monthly, and custom time ranges

## Update Frequency

TerraQuake API fetches data from INGV in real-time:

* **Automated updates**: Continuous synchronization with INGV sources
* **No caching delays**: Data is fetched directly from INGV for each request
* **Event revisions**: INGV may update event details (magnitude, location) as analysis improves

> [!NOTE]
>
> INGV events include a `version` number that increments when event data is refined or updated.

## Data Accuracy and Reliability

### Quality Assurance

* **Authoritative Source**: INGV is the official Italian government institution for seismic monitoring
* **Professional Network**: Data comes from a network of professional seismic stations across Italy
* **Peer-Reviewed**: INGV follows international seismological standards and protocols
* **Event Verification**: All events are verified and classified by expert seismologists

### Magnitude Types

INGV reports various magnitude types:

* **ML** (Local Magnitude): Most common for regional events
* **Mw** (Moment Magnitude): Used for larger earthquakes
* **Md** (Duration Magnitude): Alternative calculation method

### Location Precision

Coordinates are provided with decimal precision:

* **Latitude/Longitude**: Typically precise to 4 decimal places (\~11 meters)
* **Depth**: Reported in kilometers below sea level

## Station Network Data

In addition to earthquake events, TerraQuake API provides access to INGV's seismic monitoring station network:

* **Station locations**: GeoJSON formatted station positions
* **Operational status**: Active and inactive stations
* **Network information**: INGV network (IV) station details
* **Station metadata**: Equipment information and operating periods

> **[INGV FDSN Station Service](http://webservices.ingv.it/fdsnws/station/1/)**
>
> Access detailed technical documentation for INGV's station web services

## Additional Resources

> **[INGV Earthquake Portal](http://terremoti.ingv.it/)**
>
> View real-time earthquakes on INGV's official portal

> **[INGV Web Services](http://webservices.ingv.it/)**
>
> Technical documentation for INGV's web services

> **[FDSN Standards](https://www.fdsn.org/webservices/)**
>
> International standards for seismological data services

> **[GeoJSON Specification](https://geojson.org/)**
>
> Learn more about the GeoJSON data format

## Data Limitations

> [!WARNING]
>
> While TerraQuake API strives to provide accurate real-time data, please note:
>
> * Data is dependent on INGV's availability and service status
> * Very recent events (within minutes) may not yet be available
> * Event parameters may be revised as INGV refines their analysis
> * The API is intended for informational and research purposes, not emergency response

## Attribution

When using data from TerraQuake API, please acknowledge the data source:

```
Data provided by INGV (Istituto Nazionale di Geofisica e Vulcanologia)
via TerraQuake API
```

For academic publications, please cite both INGV and TerraQuake API appropriately.


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