RRI.CO.ID, Padang - The Geological Agency of the Ministry of Energy and Mineral Resources (ESDM) reported that seismic activity at Mount Marapi in West Sumatra remains dominated by emission earthquakes and non-harmonic tremors, according to the latest evaluation period from April 1 to 15, 2026.

Despite the ongoing volcanic activity in Agam and Tanah Datar Regencies, officials indicate that the volcano’s energy levels have not shown a significant upward trend. The Acting Head of the Geological Agency, Lana Saria, noted that while activity continues, the internal pressure within the volcano appears relatively contained.

“Seismicity data for Mount Marapi was dominated by emission quakes and non-harmonic tremors during the April 1-15, 2026 period,” Lana said in a written report received in Padang on Tuesday, April 21, 2026, as quoted by Antara.

The Agency’s monitoring stations recorded a diverse seismic profile over the last fortnight, including five eruption earthquakes, 61 emission earthquakes, and 103 non-harmonic tremors. The data also showed eight low-frequency earthquakes, eight shallow volcanic quakes, and 17 deep volcanic quakes, alongside various local and distant tectonic events. One tectonic earthquake was felt at an intensity of III MMI (Modified Mercalli Intensity).

Visually, the volcano’s peak alternated between clear views and heavy fog. Observers noted white and gray plumes rising from the main crater, reaching heights of 50 to 600 meters. According to the agency, the visual intensity of these emissions has remained stable compared to previous observation periods.

Current seismic indicators, such as the Real-Time Seismic Amplitude Measurement (RSAM), continue to fluctuate around the baseline, suggesting that there is no significant accumulation of energy within the mountain. Furthermore, the variation in seismic velocity (dv/v) has stayed within a low to medium range, reflecting minor changes in the stiffness of the volcano's shallow medium without showing a continuous downward trend that would signal a major impending event.

The Geological Agency concluded that there is currently no evidence of an increased magma supply from deeper levels. "Based on the evaluation of monitoring data in the last two weeks, Mount Marapi's activity generally still shows a fluctuant pattern," Lana added, emphasizing that coherence levels remain stable. ***