Reply to Comments on "Thermoluminescence and optically stimulated luminescence signals from volcanic ash: History of volcanism in Barren Island, Andaman Sea" by MA Alam and D. Chandrashekaram

The results of experiments which characterise the optically stimulated luminescence (OSL) signals of an ash sample (BI07-TL-05) from Barren Island are presented. The infrared stimulated luminescence signal decreases to 5% of its initial value when preheated at 150 degrees C for 10 s, suggesting that the infrared stimulated luminescence signal associated with the 290-390 nm emission in this sample arises from a single trap evicted by heating to 150 degrees C. The post-IR blue stimulated luminescence emission has greater thermal stability and arises from traps which are emptied by heating to temperatures between 120 degrees C and 240 degrees C. Dose recovery experiments demonstrate that a laboratory dose can be reliably determined to within 5% for the post-IR blue stimulated luminescence signal. However, the fading rate for the post-IR blue stimulation is high, and the g-value is estimated to be (9.6 +/- 3.5)% per logarithmic decade for BI07-TL-05. (C) 2009 Elsevier B.V. All rights reserved.