Short answer. BMKG runs the Indonesia Tsunami Early Warning System (InaTEWS) and must issue a first tsunami warning within 3 minutes of an earthquake 1. Warnings reach the public through local governments and BPBD, coastal sirens, SMS blast, digital TV, the InfoBMKG app and the SIRITA siren app 234. No national cell broadcast system was found in operation.
How fast does BMKG issue a tsunami warning?
According to BMKG's description of its procedure (April 2026) 1:
| Step | Timing 1 |
|---|---|
| First warning | under 3 minutes after the earthquake |
| Second warning | within 10 minutes |
| Updates | at 30 to 60 minutes |
| End of warning | at most 120 minutes after the first estimated arrival |
BMKG's own words: "Dalam waktu kurang dari 3 menit setelah gempa, BMKG harus memberikan peringatan pertama" (within less than 3 minutes after the earthquake, BMKG must issue the first warning) 1.
What are the warning levels?
BMKG's April 2026 release names three levels: Waspada (advisory), Siaga (alert) and Awas (warning, the highest) 1. The wave heights and actions attached to each level are reported in the press but were not found in an official BMKG text, so they are not given here. Follow the instructions of your local government and BPBD.
Do sirens still work?
Coastal tsunami sirens exist, but BMKG noted in October 2021 that many had stopped working because of their age 2. It launched SIRITA, an Android app that "akan berbunyi keras layaknya sirine apabila BMKG mengeluarkan peringatan dini" (sounds loudly like a siren when BMKG issues an early warning), and that helps local governments relay evacuation orders 2.
Will I get an alert on my phone?
By SMS blast, not cell broadcast. The Ministry of Communication and Digital Affairs (Komdigi) and BMKG say the early warning system developed since 2016 through SMS blast has been extended to digital TV broadcasts since August 2024 34. Cell broadcast has been announced as a plan, but no operating system was found.
What if mobile networks fail?
BMKG's EWS Radio Broadcaster, launched in 2021, relays warnings by voice over volunteer radio networks (RAPI, ORARI) 2. A portable radio is on the BNPB bag list 5. See /guides/emergency-radio.
Which apps are official?
- InfoBMKG: BMKG's app for weather, earthquakes and tsunamis.
- SIRITA: BMKG's tsunami siren app (2021) 2.
- inaRISK: BNPB's hazard and risk portal (https://inarisk.bnpb.go.id/).
Should I wait for the warning?
Not on the coast. BNPB says that natural signs (strong or vertical shaking, the sea receding, a roaring sound) mean go to high ground at once, within the first 10 minutes, without waiting for official instructions 5. See /guides/tsunami and public shelters.
Frequently asked questions
Does Indonesia have cell broadcast alerts?
No operating system was found. Alerts reach phones by SMS blast 34.
What is SIRITA?
A BMKG Android app, launched in 2021, that sounds like a siren when BMKG issues a tsunami warning 2.
How long does a tsunami warning last?
BMKG ends it at most 120 minutes after the first estimated arrival time 1.
Who tells me to evacuate?
BMKG issues the warning; local governments and BPBD direct the evacuation 12.
Sources
- BMKG — Pascagempabumi M 7.6, BMKG Sampaikan Analisis dan Timeline Peringatan Dini Tsunami — https://www.bmkg.go.id/berita/utama/pascagempabumi-m-7-6-bmkg-sampaikan-analisis-dan-timeline-peringatan-dini-tsunami (accessed 2026-10-20)
- BMKG — Hadang Potensi Tsunami di Selatan Jawa, BMKG Luncurkan EWS Radio Broadcaster dan SIRITA — https://www.bmkg.go.id/siaran-pers/hadang-potensi-tsunami-di-selatan-jawa-bmkg-luncurkan-ews-radio-broadcster-dan-sirita (accessed 2026-10-20)
- BMKG — Perkuat Sistem Peringatan Dini Bencana, BMKG-Kemkomdigi Optimalkan Infrastruktur Komunikasi — https://www.bmkg.go.id/berita/perkuat-sistem-peringatan-dini-bencana-bmkg-kemkomdigi-optimalkan-infrastruktur-komunikasi (accessed 2026-10-20)
- Kementerian Komunikasi dan Digital (via InfoPublik) — Siaran Pers: Kemkomdigi-BMKG Perkuat Sistem Peringatan Dini untuk Hadapi Cuaca Ekstrem — https://infopublik.id/kategori/siaran-pers/907390/siaran-pers-kemkomdigi-bmkg-perkuat-sistem-peringatan-dini-untuk-hadapi-cuaca-ekstrem (accessed 2026-10-20)
- BNPB (Pusat Data, Informasi dan Komunikasi Kebencanaan) — Keluarga Siaga Bencana – Panduan Anti Panik Saat Gempa, Banjir & Krisis Darurat — https://perpustakaan.bnpb.go.id/inlislite/uploaded_files/temporary/DigitalCollection/OThjMzRiZDFlMDU2OWYzNzQ5ZjliYWI0Nzg3ODkxMTQxNTE0NDIzNg==.pdf (accessed 2026-10-20)
Turn this into action
Your plan for Indonesia, worked out for your household.
- Water, food and equipment counted for each person and pet
- The nuclear plants and zones around your home
- Phaenyx Safe: one tap to tell your people you are safe
Sources
- BMKG · Pascagempabumi M 7.6, BMKG Sampaikan Analisis dan Timeline Peringatan Dini Tsunami checked 2026-10-20
- BMKG · Hadang Potensi Tsunami di Selatan Jawa, BMKG Luncurkan EWS Radio Broadcaster dan SIRITA checked 2026-10-20
- BMKG · Perkuat Sistem Peringatan Dini Bencana, BMKG-Kemkomdigi Optimalkan Infrastruktur Komunikasi checked 2026-10-20
- Kementerian Komunikasi dan Digital (via InfoPublik) · Siaran Pers: Kemkomdigi-BMKG Perkuat Sistem Peringatan Dini untuk Hadapi Cuaca Ekstrem checked 2026-10-20
- BNPB (Pusat Data, Informasi dan Komunikasi Kebencanaan) · Keluarga Siaga Bencana – Panduan Anti Panik Saat Gempa, Banjir & Krisis Darurat checked 2026-10-20