Using an earthquake app offline: what stays available without a connection

Start with the material included in the app

Earth & Volcano Explorer includes 20 lessons, illustrations, six types of learning models and its own geographic atlas. These do not need to be fetched again whenever you open them. The bundled volcano catalog contains 170 U.S. volcanoes. It is not a global encyclopedia and does not contain a complete eruption history.

The interface and learning content support 12 languages, with dictionaries and fonts included in the app. Changing the language does not require a translation service. Source names and external reports may still use their original language. Opening an official report in your browser is a separate network request, even when the lesson linking to it is available locally.

A cached event feed is an earlier snapshot

The app retrieves a USGS catalog covering the past 24 hours and stores received data locally. On a later launch, saved events can appear before a new network response arrives. Check the update time and stale-data indicators: markers on a map do not prove that the connection is working. Without a fresh response, later events and source revisions cannot reach the app.

Suppose you refresh in the evening and reopen your phone without service the next morning. Yesterday’s cards may still be useful to read, but they cannot describe everything that happened overnight. The 24-hour scope is a working feed, not an unlimited historical archive. Filters also affect which saved records remain visible.

Separate the atlas from online street maps

The built-in atlas supplies geographic context without downloading street tiles. The OpenStreetMap street layer needs a connection for tiles unavailable on the device; the app does not offer downloadable offline street-map packages. A saved region is a local name, coordinate and radius, rather than a downloaded neighborhood map or an official hazard boundary.

Language, theme, units, reduced motion, regions, favorites and checklist marks are local settings. No account is required, and the app has no advertising. The app has no synchronization service of its own. Android system backup is not disabled; its operation depends on OS settings. Deleting local data in settings clears saved regions, bookmarks, checklist marks and the cache. Keep an important family plan on paper as well.

Check the phone you will actually carry

A calm check on your device is more useful than assuming that a cache makes every screen available. A full native-device check with all network access disabled remains outstanding in the current project. Do not make the app your only copy of important information. Try it before leaving and record which material is available on your phone.

• While connected, refresh the catalog and note when the data was received.
• Open a lesson, the checklist and the built-in atlas, then disable both Wi-Fi and mobile data.
• Relaunch the app and distinguish available material from old records and network errors.
• Reconnect, refresh and compare the time. Keep paper contacts and a local route with your emergency supplies.

Plan separately for emergency information

The app does not provide earthquake early warning or currently deliver real background push notifications. Adding a region does not activate working notification delivery. Tsunami bulletins require a configured backend, and the current APK has no backend address configured. An empty screen during a connection problem cannot establish that no threat exists.

Learn your local official information channels and backup options in advance. CDC recommends following emergency information after an earthquake, including through a battery-operated radio. Local instructions take priority. Use saved material for preparation and understanding records, alongside a separate household communication plan.