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. Search for "Tsunami Watch" by Trevlo Tech LLC, then download and install it on your device.

First launch — Onboarding

When you open Tsunami Watch for the first time, you'll be guided through a short onboarding flow that sets up the core features of the app.

1

Push notification permission — The app will ask for permission to send you push notifications. This is used to alert you when a tsunami threat is issued for one of your watched regions. You can tap "Allow" or grant permission later in Settings. Real-time notifications cannot be received without push notification permission.

2

Select your watched regions — Choose the coastal areas you want to receive alerts for. You can select multiple regions (your hometown, a family member's location, a place you travel frequently, etc.). You can add or remove regions at any time after setup.

3

Location permission — The app will ask for permission to access your device location. This is used only on your device to show your proximity to active tsunami threats. Your location is never sent to our servers. You can tap "Allow While Using App" or grant permission later in Settings. Choosing not to grant location access will not affect alert delivery.

4

Enable Demo Mode — To get a feel for the app, you can enable demo mode. While activated, your device will receive test alerts approximately every 5 minutes. This allows you to kick the tires and ensure push notifications are being delivered successfully.

5

Purchase a subscription — Receiving push notifications for real threats requires an active subscription. Here you can view available subscription plans and make a purchase. Or, you can skip purchasing a subscription to get a feel for the app first, making your purchase later in settings.

Tip: Push notifications and an active subscription are required to receive real-time alerts.

Dashboard

The Dashboard is the main screen of Tsunami Watch. It gives you an at-a-glance overview of current tsunami bulletin activity across all your watched regions.

Threat status indicator

At the top of the Dashboard you'll see a global status indicator that reflects the highest-severity active bulletin across all your watched regions:

  • ALL CLEAR — Green - No active threats in your watched regions. All clear.
  • THREAT — Red - An active alert has been issued for one or more of your watched regions.
Important: An "All Clear" status applies only to your watched regions. 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 regions. 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.

Refreshing data

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

Alert Details

Tapping a bulletin on the Dashboard 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.
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.

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 Regions

Watched regions are the coastal areas you've selected to monitor. Push notifications and Dashboard status are scoped to these regions — you'll only be alerted when a bulletin affects one of your watched regions.

Adding a region

1

Go to Settings → Watched Regions.

2

Find the region you are interested in.

3

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

Removing a region

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

How notifications are scoped

A push notification is sent when a new bulletin is issued that includes at least one of your watched regions in its affected zones. If a bulletin affects only regions 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 region to expand it. Turn on the toggle for the no threat item.

Tip: Add regions for all the coastal areas you care about — home, family, and travel destinations. Adding more regions increases your safety net without reducing alert quality.

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 regions
  • 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 Dashboard access — browse active bulletins at any time
  • Alert Details — read the complete official bulletin text
  • Interactive Map — view threat zones and event locations
  • Watched Regions — manage your list of monitored coastlines

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 is a feature that allows you to test the app without receiving real-time push notifications. When enabled, you will receive test alerts approximately every 5 minutes. This allows you to kick the tires and ensure push notifications are being delivered successfully. A "Test" region will show on your dashboard where the test alerts will be displayed. Toggle demo mode on and off from the Demo Mode page.

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.