<p>South-East Asia is one of the most tectonically complex regions on Earth. North Borneo in particular is home to a number of intriguing features, the formation of which is not fully understood. These include the North-West Borneo trough, the rapidly uplifted 4000m high Mt Kinabalu and the uplifted circular sedimentary basins such as the Maliau Basin. To study North Borneo's tectonics in depth we deployed a new dense temporary network of 46 broadband seismometers across the regionin a semi-regular grid pattern with approximately 40km spacing. This closely spaced network, which operated for 22 months, allows a high-resolution seismic analysis of the crust and mantle under North Borneo. Here, we use ambient noise cross-correlations to measure phase velocities of surface waves. We then use the phase velocities to analyze the crustal and upper mantle structure.</p>
Crust and upper mantle structure beneath the Pacific Northwest from joint inversions of ambient noise and earthquake data