# Trigger Alerts

Grillo Cloud can email your team when a [trigger](/dashboard/triggers) reaches an alert level. The level is measured as horizontal peak ground acceleration (PGA), in mg.

The alert level is separate from the [trigger threshold](/dashboard/sensors/recording-mode). The threshold decides when a sensor records; the alert level decides which of those recordings are worth an email. For example, a sensor with a 5 mg threshold and a 50 mg alert level records every disturbance above 5 mg, and emails you only when shaking reaches 50 mg.

## Turn on alerts

Owners and admins of Structural projects can set up alerts:

1. Open **Project Settings**.
2. Under **Trigger alerts**, enter an **Alert level (mg)** between 1 and 2000 mg. 1000 mg is 1 g.
3. Under **Recipients**, add up to 25 email addresses. Recipients do not need a Grillo Cloud account. If you add none, alerts go to the project's owners and admins.
4. Select **Save**.
5. Select **Send test email** to send a sample alert to yourself.

![Trigger defaults and Trigger alerts in Project Settings](/img/screenshots/project-settings-triggers.png)

To turn alerts off, clear the alert level and save. The setting then shows **Off**.

### A different level for one sensor

A sensor in a busy location may need a higher level than the rest of the project. Open the sensor's details, select **Edit**, turn off **Use project alert level** under **Recording mode**, and enter the sensor's own **Alert level (mg)**.

## What you receive

Each recipient gets their own email.

1. **Alert.** Sent as soon as the trigger's horizontal PGA reaches the alert level, normally within seconds of the data reaching Grillo. It gives the peak so far.
2. **Summary.** Sent when the trigger ends, with its final values.

Both emails give the project, the sensor's station code and location name, the alert level that was crossed, the horizontal PGA in mg and %g, the PGA on each axis, the vertical PGV, the dominant frequency, the peak time in UTC, and the duration, with a link to the trigger in Grillo Cloud.

## Limits

To keep a busy sensor from filling your inbox:

- **Per sensor:** at most one alert every 10 minutes. Triggers that cross the level in that time are counted in the next summary.
- **Per project:** at most 20 alerts a day. After that, recipients get one digest listing each sensor's triggers and largest PGA.
- **Trigger storm:** a sensor that triggers more than 15 times in an hour gets one trigger storm email, with a suggested threshold. It sends no more alerts until it has been quiet for 6 hours.

The suggested threshold is twice the typical horizontal PGA of that hour's triggers. If you accept it, [raise the sensor's threshold](/dashboard/sensors/recording-mode#change-a-sensors-threshold).

## On the trigger page

Each [trigger's details](/dashboard/triggers#trigger-details) show **Email alert**:

| Status | Meaning |
|---|---|
| **Sent** *time* **to** *n* **recipients** | The alert went out |
| **Not sent: this sensor had an alert in the previous 10 minutes** | The per-sensor limit applied |
| **Not sent: this sensor is triggering too often (trigger storm)** | The sensor is in a trigger storm |
| **Not sent: the project reached its daily alert limit** | The project had 20 alerts today |
| **No summary: trigger storm** or **No summary: daily alert limit reached** | The summary was held back for the same reasons |

A trigger that never reached the alert level shows no alert.

## If an alert did not arrive

1. Check the trigger's **Email alert** status.
2. Confirm the trigger's horizontal PGA reached the alert level, using the sensor's own level if it has one.
3. Check spam or junk folders, and ask your email administrator whether mail from Grillo is being blocked.
4. Use **Send test email** to confirm delivery to your address.

:::warning Not a safety system
Trigger alerts are sent over email and can be delayed by mobile networks and email providers. Do not rely on them alone for life-safety decisions.
:::