User Guide

Everything you need to get the most out of Tsunami Watch.

Getting Started

Installing the app

Tsunami Watch is available on the Apple App Store and Google Play. Download it directly, or search for "Tsunami Watch" by Trevlo Tech LLC.

Download on the App Store Get it on Google Play

First launch — Onboarding

When you open Tsunami Watch for the first time, you'll be guided through a six-step onboarding flow. Several steps are optional — you can finish setup later in Settings, or walk through the flow again anytime from Settings → Setup guide.

1

Welcome — A brief introduction to Tsunami Watch. Tap Get started to begin.

2

How it works — A quick overview of the alert pipeline: an earthquake is detected, an official bulletin is issued, and Tsunami Watch delivers that bulletin to your phone.

3

Choose your coastlines — Select the coastal areas you want to monitor. For many large coastlines you can also pick specific areas (countries, states, provinces, or territories) under Areas to monitor. Leave that list empty for full coverage of the coastline. Tap Find my nearest coastlines to use your location and auto-select nearby regions (location is used only on your device for this suggestion). Enable at least one coastline to tap Continue, or tap I'll choose later to skip for now.

4

Stay alerted — Turn on push notifications so official bulletins reach you immediately, even when the app is closed. Tap Turn on notifications and grant permission when prompted. To set this up later, tap Continue to proceed without enabling notifications yet. If you previously denied permission, use Having trouble? Open system settings.

5

See it in action — Optionally enable test alerts to explore the app with sample bulletins. Tap Send me test alerts to receive periodic test notifications (about every 15 minutes while enabled), or No thanks, continue to skip. Test alerts require that you completed the notification step.

6

Unlock live alerts — A premium subscription activates real-time push notifications for live tsunami bulletins on your watched coastlines. Tap View plans to subscribe, or Continue to the app to explore first and subscribe later from Settings → Subscription.

Tip: Push notifications and an active subscription are required to receive real-time alerts for live threats. You can revisit any part of setup from Settings → Setup guide.

Home

The Home tab is the main screen of Tsunami Watch. It gives you an at-a-glance overview of current tsunami bulletin activity across your watched coastlines (and any areas you’ve selected within them).

Threat status indicator

At the top of the Home screen you'll see a global status indicator that reflects the highest-severity active bulletin across your watched coastlines:

  • ALL CLEAR — Green - No active threats in your watched coastlines. All clear.
  • THREAT — Red - An active alert has been issued for one or more of your watched coastlines.
Important: An "All Clear" status applies only to your watched coastlines and selected areas. Bulletins may be active in other parts of the world not on your list.

Bulletin list

Below the status indicator, you'll see a scrollable list of active bulletin alerts relevant to your watched coastlines. If you’ve narrowed a coastline with Areas to monitor, only alerts that overlap those areas appear here. If location services have been enabled, the alerts will be sorted by distance from you, with the nearest alert listed first. Each bulletin card shows:

  • Alert level (Warning / Watch / Advisory / Threat)
  • Issuing agency
  • Affected region
  • Issue time
  • A brief summary of the situation and location

Tap any bulletin card to see the full Alert Details.

Silencing an event from Home

If an event is producing repeated updates, tap the bell icon on a bulletin card to silence further push notifications for that event only. Other events and coastlines will still notify you. Tap again (or choose Resume) when you want alerts for that event again.

Refreshing data

The app periodically syncs with the official bulletin feeds in the background. Pull down on the Home screen list to manually refresh at any time.

Alert Details

Tapping a bulletin on the Home screen opens the Alert Details screen, which shows the full official bulletin text along with structured information extracted from it.

What each field means

  • Alert Location — Location name, latitude and longitude, and distance from your current location (if location services have been enabled). This is the location where the tsunmai is expected to impact, not the location of the earthquake which caused the tsunami.
  • Alert Level — Warning, Watch, Advisory, Threat, or Information (see FAQ for definitions).
  • Issuing Agency — The official government organization that issued the bulletin (e.g., NTWC, PTWC).
  • Bulletin Time — When the bulletin was issued.
  • Alert Category Description — A description of what the alert category means.
  • Alert Level Detail — Severity, urgency, and certainty indicators. Not all indicators are available from all agencies.
  • Recommended Actions — Actions recommended by the issuing agency.
  • Earthquake Information — Information on the earthquake which triggered the event, such as magnitude, depth, location, time the event occurred, event coordinates, and distance from your current location (if location services are enabled).
  • Interactive Map — An interactive map which shows the earthquake location and the alert location (expected impact).
  • Bulletin Text — The full, unmodified official bulletin text from the issuing agency. This includes additional details such as predicted times of arrival for various locations, observed wave heights, and other available information.

Silence alerts for this event

Near the top of Alert Details you’ll find a control to stop further push notifications for this event only — useful when updates keep arriving but you no longer need them (for example overnight). Tap Silence alerts for this event to confirm. The screen will show Notifications silenced; tap Resume alerts anytime to turn them back on.

Silencing one event does not affect other events or your watched coastlines.

Tip: The bulletin text from the official agency always takes precedence. Tsunami Watch does not alter or summarize official alert content.

Interactive Map

The Map tab provides a real-time visual overview of tsunami activity. It uses Google Maps as the base layer, overlaid with threat indicators tied to current bulletins. Markers follow the same filtering as Home and push notifications: only alerts for your watched coastlines (and selected areas, if any) are shown.

Navigating the map

Pinch to zoom in and out, and drag to pan. Standard map gestures apply.

Alert markers

Active bulletin alerts are shown as colored markers on the map:

  • Red markers — Areas under a Tsunami Warning or threat.
  • Orange markers — Areas under a Tsunami Watch.
  • Yellow markers — Areas under a Tsunami Advisory.

Tap on any marker to see a summary of the associated bulletin. Tap the summary card to open the full Alert Details.

Event epicenter marker

When an active bulletin is associated with a seismic event, an orange, pulsing marker is placed at the earthquake epicenter. Tap it to see the event's magnitude. Tap the pop up to view the associated bulletin.

Your location

If you've granted location permission, a blue dot shows your current position on the map. This helps you visually gauge your proximity to any active threat.

Tip: Use the map to get a spatial understanding of where a threat is relative to your location — but always rely on official agency guidance for evacuation decisions.

Watched Coastlines

Watched coastlines are the coastal products you've selected to monitor. Push notifications, Home screen status, and map markers are scoped to these coastlines — and, optionally, to specific areas within them.

Adding a coastline

1

Go to Settings → Watched Coastlines.

2

Find the coastline you are interested in. You can also tap Find my nearest coastlines to suggest regions near you.

3

Turn on the toggle next to any coastline to add it to your watchlist.

Removing a coastline

Turn off the toggle for any coastline you no longer wish to receive alerts for.

Areas to monitor

Many large coastlines let you narrow alerts to specific areas — countries, states, provinces, or territories — without sharing GPS for targeting.

1

In Settings → Watched Coastlines, expand a coastline that supports areas.

2

Under Areas to monitor, search the A–Z list and select the places you care about.

3

Leave the list empty for full coverage of that coastline. With areas selected, push notifications, Home, and the map only include alerts that overlap those areas.

The app may also prompt you optionally — for example after you start watching a large coastline, or when you travel — to narrow alerts to a relevant area.

Privacy: Area targeting stores only the areas you choose — not your GPS coordinates. Location remains optional for map and distance features.

How notifications are scoped

A push notification is sent when a new bulletin is issued that includes at least one of your watched coastlines (and matches your selected areas, if any). If a bulletin affects only places you aren't watching, you won't be notified — this prevents alarm fatigue from events far from your areas of interest.

Information Bulletin Alerts

Information bulletins do not represent a tsunami threat, but indicate that an earthquake has occurred in the region. If you want to receive alerts for these bulletins, tap the coastline to expand it. Turn on the toggle for the no-threat / information item.

Tip: Add coastlines for all the coastal areas you care about — home, family, and travel destinations. Use Areas to monitor on large coastlines when you only need a subset of alerts.

Notifications

Push notifications are the most critical feature of Tsunami Watch. They are designed to alert you even when the app is closed and your device is locked.

Enabling push alerts

1

Go to Settings → Notifications.

2

Toggle on "Enable Push Alerts".

3

Grant notification permission when your device prompts you. If you previously denied permission, enable it via your device settings: System Settings → Tsunami Watch → Notifications → Allow.

Notification sound

Tsunami Watch uses configurable high-urgency alert sounds for push notifications. The sound to use can be configured for each alert category in Settings → Notification Sounds. For threat categories, pick a sound that will wake you if you're asleep during a middle-of-the-night event.

Do Not Disturb

If you use Do Not Disturb or a Focus mode on your device, we strongly recommend adding Tsunami Watch as an allowed app or setting it as a priority sender so alerts can break through.

  • iOS: Settings → Focus → Do Not Disturb → Apps → Add Tsunami Watch
  • Android: Settings → Notifications → Do Not Disturb → Exceptions → Add Tsunami Watch

Premium subscription requirement

Push notifications require an active premium subscription. This covers the server infrastructure cost of monitoring feeds and delivering alerts 24/7. See the Subscriptions section for more details.

Note: Enabling notifications without an active subscription will not result in push alerts being delivered, even if the toggle appears on.

Subscriptions

Tsunami Watch is free to download. A premium subscription unlocks real-time push notifications.

What the subscription includes

  • Real-time push notifications for tsunami threats, warnings, watches, and advisories in your watched coastlines
  • Notifications delivered even when the app is closed or your device is locked
  • High-urgency alert sound designed to wake you from sleep

What's free

  • Full Home screen access — browse active bulletins at any time
  • Alert Details — read the complete official bulletin text
  • Interactive Map — view threat zones and event locations
  • Watched Coastlines — manage your monitored coastlines and optional areas

Subscribing

1

Go to Settings → Subscription to see available subscription plans.

2

Review the subscription options and pricing, then confirm your purchase through your device's App Store or Google Play account.

Managing or cancelling your subscription

Subscriptions are managed entirely through the Apple App Store or Google Play. Trevlo Tech LLC does not process or store your payment information.

  • iOS: Settings → [Your Name] → Subscriptions → Tsunami Watch
  • Android: Google Play → Profile → Payments & subscriptions → Subscriptions → Tsunami Watch

Cancelling your subscription will end push notification delivery at the end of the current billing period. All other app features remain available. You will receive a push notification from Tsunami Watch informing you when your subscription has ended.

Tip: The cost of the subscription directly supports the server infrastructure that monitors official feeds and pushes alerts to your device around the clock.

Other Settings

Access Settings by tapping the gear icon in the bottom navigation bar.

Demo Mode

Demo mode sends test bulletins so you can explore the app without waiting for a real event. When enabled, your device receives test alerts approximately every 15 minutes. This lets you verify that push notifications are working and preview the map, threat levels, and alert details with sample data. A test region will appear on your home screen where the test alerts are displayed. Toggle demo mode on and off from Settings → Demo Mode.

Location Services

Setup location display settings, distance units, and GPS location accuracy.

Data Management

See how much data the app is storing, clear the stored data, or download (sync) current tsunami data.

Diagnostics

Turn on or off crash reporting and analytics. This data is used to help us fix bugs and improve the app.

Help and Support

View help resource and information on contacting support.

About

Displays the app version number, links to data sources, the Privacy Policy, and Trevlo Tech LLC website. Providing the version number when contacting support is helpful.