Walter D. Mooney Ying Zhang 2023 <p><span>Characterizing the crustal structure of Indonesia is important to gain a better understanding of its geodynamic evolution and improve seismic hazard assessments in the area. However, a unified crustal model of the entire Indonesian region and its surroundings is lacking. We present new maps of crustal thickness and bulk V</span>_p<span>/V</span>_s<span>&nbsp;ratio in Indonesia and the surrounding area that are obtained using P-wave receiver functions at 36 seismic stations from several permanent regional networks. The measured crustal thickness varies from ∼24&nbsp;km to ∼38&nbsp;km. The thickest crust, ∼38&nbsp;km, is beneath Flores Island, southern Maluku, and neighboring northernmost Australia, whereas the thinnest crust, ∼24&nbsp;km, is found under eastern Malaysia. Thus, crustal thickness varies by ∼14&nbsp;km (from ∼24&nbsp;km to ∼38&nbsp;km) despite the small changes in elevation at the measurement points. The V</span>_p<span>/V</span>_s<span>&nbsp;ratios are 1.79</span><span class="math"><span id="MathJax-Element-1-Frame" class="MathJax_SVG" data-mathml="<math xmlns=&quot;http://www.w3.org/1998/Math/MathML&quot;><mo is=&quot;true&quot;>&amp;#xB1;</mo></math>"><span class="MJX_Assistive_MathML">±</span></span></span><span>0.11, with high values (&gt;1.85) found along the Banda-Sunda arc-trench system. We attribute these high values to: (1) the presence of mafic island arc and oceanic crust and (2) partial melting within this volcanic region, which causes a larger decrease in S-wave velocities compared with P-wave velocities. The comparison of the seismic properties of Indonesian island arc crust, particularly the V</span>_p<span>/V</span>_s<span>&nbsp;ratio, with laboratory measurements and the petrology of the exhumed Talkeetna island arc, Alaska, allows us to infer the crustal composition of Indonesian island arc crust.</span></p> application/pdf 10.1016/j.tecto.2023.230033 en Elsevier Regional crustal structure of Indonesia from receiver functions article