Seismic Activity in Indonesia

Indonesia is a seismically very active country. The United States Geological Survey (USGS) lists Indonesia as the country with the most earthquakes in the world¹.

It lies on the Pacific Ring of Fire, the world’s greatest volcanic and seismic belt, where 81 percent of recorded earthquakes occur. And it is at the junction of three major tectonic plates – the Indo-Australian, Eurasian, and Pacific plates – as well as several others (Philippine Sea plate, Caroline plate, etc.).

According to the United States Geological Survey (USGS), in 2020 within a range of 300 km, 1692 earthquakes with a magnitude of more than 4.0 occurred in Indonesia (among them were 1471 between 4.0 and 4.9, 113 earthquakes with a magnitude between 5.0 and 5.9, and 10 earthquakes with a magnitude above 6.0), which is 37 less than the subsequent year of 2021, when we witnessed 1730 earthquakes with a magnitude above 4.0 (among them were 1555 with a magnitude between 4.0 and 4.9, 121 with a magnitude between 5.0 and 5.9, and 11 above 6.0). This year the USGS reports 809 earthquakes above magnitude 4.0.

Besides being an earthquake-prone country, Indonesia is frequently struck by volcanic eruptions, floods, and tsunamis, all due to its location on the Ring of Fire. Along Sumatra, Java, Bali, and the islands of the eastern part of Indonesia, more than 200 volcanoes are located. Due to its disastrous natural disasters, Indonesia has made global headlines on several occasions in recent years with worldwide reports on the loss of hundreds of thousands of people’s lives and the devastating effects incurred on the infrastructure and economy.

For example, on September 28, 2018, a magnitude 7.5 earthquake triggered a large tsunami causing more than 2,000 fatalities, more than 4,000 serious injuries, more than 600 missing people, and about 68,000 damaged or destroyed houses³. Also, on January 1, 2021, a magnitude 6.2 earthquake in Sulawesi caused the loss of 105 lives and more than 3,000 people injured².

Below is a selected list of recent earthquakes that caused severe damage and at least 20 fatalities⁴:

LOCATION        DATE                MAGNITUDE   CASUALITIES
Lombok          05-08-2018                  6.9                    565
Lombok          29-07-2018                  6.4                    20
Sumatra         07-12-2016                  6.5                    104
Sumatra         02-07-2013                  6.1                    42
Sumatra         25-10-2010                  7.7                    435
Sumatra         30-09-2009                  7.6                    1,117
Java               02-09-2009                  7.0                    81
Sumatra         12-09-2007                  8.5                    23
Sumatra         06-03-2007                  6.4                    68
Java               17-07-2006                  7.7                    668
Java               25-05-2006                  6.4                    5,780
Sumatra         28-03-2005                  8.6                    1,346
Sumatra         26-12-2004                  9.2                    283,106

Earthquakes are one of the biggest threats to Indonesia in terms of natural disasters as they often strike in populous areas such as the bigger cities, making many people lose their lives, homes, and property. According to the USGS, earthquakes with a magnitude of around five on the Richter scale occur almost daily in Indonesia, but often with little to no damage. More devastating earthquakes are the ones with a magnitude above six on the Richter scale.

The great degree of material damage is exacerbated by the poor state of the country’s infrastructure, which only increases the devastating consequences of earthquakes.

You might ask, why haven’t more solid, earthquake-resistant facilities been developed in such an earthquake-prone country? It could be because of mismanagement, limited financial resources, a lack of skills, or corruption⁴.

Because of the weak infrastructure, even moderately strong earthquakes can result in the collapse of buildings and the loss of lives. If a strong earthquake were to strike a mega-city such as Jakarta, Surabaya, Medan, or another with an extremely high population density, the consequences could be as never seen before.

When it comes to natural disasters in Indonesia, we need to keep in mind that we are talking about a relatively poor country, where many people struggle to get through the day. A poor country that lacks basic necessities needs even more time and resources to recover after suffering a natural disaster. The most vulnerable victims are people with low income and those living in poverty.

The strongest and the deadliest earthquake in Indonesia occurred on December 26, 2004. An underwater, magnitude 9.1 earthquake triggered a 100-foot-tall tsunami killing more than 200,000 people and leaving thousands of communities in ruins².

The five largest earthquakes since 2000 in Indonesia are:
- M8.2 Wharton Basin 2012-04-11 earthquake;
- M8.4 Sumatra 2007-09-12 earthquake (23 fatalities, 88 injured);
- M8.6 Wharton Basin 2012-04-11 earthquake (10 fatalities, 12 injured);
- M8.6 Sumatra 2005-03-28 earthquake (1,314 fatalities, 1,145 injured);
- M9.1 Sumatra-Andaman 2004-12-26 earthquake (167,540 fatalities in Indonesia, more than 200,000 injured).

WHAT LIES AHEAD?

Indonesia already offers earthquake and tsunami early warning alerts; however, they can be sent only after the shaking has already begun. The warning comes seconds to tens of seconds in advance, leaving people only enough time to take action to protect their lives.

At Quantectum, however, the operational center forecasts earthquakes up to 64 days in advance. The operational center is a center with seismologists and other experts in the field, who are always on the lookout for the next possible major earthquake. They monitor the current events in Earth’s crust, compare it to the information from previous major events, and produce earthquake forecasting results. Based on a variety of parameters, they prepare weekly and monthly forecasts and reports based on recent earthquakes.

In the past, they correctly forecasted a number of earthquakes that occurred all around the world. You can see specific forecasted earthquakes here.

At Quantectum, we have reported on Indonesia’s earthquakes multiple times. For example, you can check our report from June 8, 2022 on the magnitude 5.8 earthquake that struck Sulawesi on June 8, 2022 here, or our report from March 14, 2022 on the magnitude 6.6 earthquake in Kepulauanbatu on March 13, 2022 here.

Sources:
¹USGS. Which country has the most earthquakes? Accessed on 2022-06-15. Available at: https://www.usgs.gov/faqs/which-country-has-most-earthquakes
²National Public Radio (NPR). 2022. Searchers dig into the rubble after an earthquake hit Indonesia. Accessed on 2022-06-15. Available at: https://www.npr.org/2022/02/26/1083275522/indonesia-earthquake-search-victims?t=1655272296065
³Worldvision. 2018 Indonesia quakes and tsunamis: Facts, FAQs, and how to help. Accessed on 2022-06-15. Available at: https://www.worldvision.org/disaster-relief-news-stories/2018-indonesia-earthquake-facts#:~:text=28%2C%202018%2C%20triggering%20a%20tsunami,the%20Indonesia%20disaster%20management%20agency.
⁴Indonesia Investments. Natural Disasters in Indonesia. Accessed on 2022-06-15. Available at: https://www.indonesia-investments.com/business/risks/natural-disasters/item243