TEMPO.CO, Jakarta – A tectonic earthquake measuring 5.1 magnitudes occurred at sea, 101 kilometers south of Kulonprogo, Yogyakarta early today, July 13, at 02:50 a.m. local times. The tremor was felt in Pangandaran of West Java until Pacitan of East Java, the Meteorology, Climatology, and Geophysics Agency (BMKG) reported.
The quake source was recorded at 8.73 degrees south latitude and 109.88 degrees east longitude, and at a depth of 46 kilometers. The BMKG’s head of quake and tsunami mitigation Daryono considered it a shallow one.
“It is caused by the subduction of the Indo-Australian plate under the Eurasian plates,” said Daryono on Monday, July 13, adding that the quake was triggered by a thrust fault as shown in the analysis of the quake mechanism.
The tremor was reportedly felt in Pacitan, Purworejo, Yogyakarta, and Wonogiri, as well as Pangandaran. There are no reports yet on casualties and aftershocks as of today, 3:15 a.m.
According to him, the quake’s epicenter was adjacent to that of the 8.1 magnitude earthquake on July 23, 1943, which heavily damaged Cilacap, Tegal, Purwokerto, Kebumen, Purworejo, Bantul, and Pacitan. A geologist from Netherlands Van Bemmelen in 1949 stated that the death toll hit 213 people, 2,096 people were injured, and 15,275 houses torn down in Central Java and Yogyakarta.
For the past three weeks, the BMKG recorded increasing earthquake activity, viz. on June 22, 5M quake in the south of Pacitan; on July 5, 5.3M quake in South Blitar; and on July 7, 5.1M quake in Lebak, 5.0M quake in South Garut, ad 5.2M quake in the south of Sunda Strait.
Daryono asserted that the public should not fret too much about the recent increase in seismic activity in southern Java. However, he called on all and the government to remain vigilant and improve disaster preparedness.