In Indonesia: Notes and Photographs From a Field Geologist

February 2, 2005

At the end of January, Kerry Sieh left Indonesia for further travel and eventual return to Caltech. Below are reports from his colleague, Caltech's John Galetzka, who remains in the field.

To see Kerry Sieh's photographs of the area, click here.

To read the report in its entirety, please click here.

Friday, January 28

Hello all,

Bambang and I swapped receivers at Bais and Simuk Islands and met up with Imam and the hired cargo boat Mentawai Indah in Tello yesterday (Thursday,) evening. We all throttled out of Tello early this morning and have been doing a nice seven knots on our way up to the village of Sinibang on Simeuleu Island. We've been showered on much of the day and currently (Friday night) find ourselves cruising past Gunung Sitoli, Nias Island. We should be in Sinabang late tomorrow morning.

Saturday, January 29

Saturday, 6 p.m. and we have Simeuleu Island in sight. We were delayed by 12 hours because of nasty seas and weather all last night up until 2 p.m. this afternoon. Poor Bambang is very seasick.

We should be getting to Sinabang, Simeuleu, around 10 p.m. this evening. All are looking forward to a nice quiet anchorage tonight and starting GPS station installation tomorrow.

Simeulue Island, Monday January 31

We're ending our second full day here in the area of Sinabang, on Simeulue Island. We started building a GPS station at the island's only airport today after getting the thumbs up from the island's chief administrator yesterday. The station should be up and running by tomorrow at noon, February 1. That includes satellite telemetry with the latest version of satellite terminal firmware from the ACeS team in Batam, Indonesia.

Bambang and I also gave a talk tonight at a gathering of island officials and foreign guests. We had no clue it was going to be such a formal event! Lobster and other delicacies for dinner, desert, and famous Aceh coffee. Thankfully our graphics and our message made up for me failing to wear long pants!

We plan to place a station near Sinabang first, followed by a station on the northern coast of Simeulue, then one somewhere near Banda Aceh. The Nias station will be last because we're expecting two receivers sent by Heather and others at Caltech, to be delivered to the Bupati's office in Gunung Sitoli.

Great news! The police in Tuapejit located all the equipment stolen from the Panjang Island station. The police are expecting that reward Kerry promised!

Other great news: there are about 30 less cockroaches on our ship due to my fancy footwork of the last 24 hours!

Wednesday, February 2, on Simeulue Island

Our fine ship and crew are all now on the extreme northern tip of Simeulue Island, anchored in a cove near a village called Lewah. This morning we left Sinabang, the island's capital on the east coast, on a late start (electric generator issues, I think) and cruised the east side of the island on our way north. I slept in late this morning to catch up on rest, but during this time my colleagues Bambang and Imam met up with the Bakosurtanal (equivalent to the USGS) that will be re-occupying Yehuda and Jeff's site (both from the Scripps Institute) here in northern Sumatra. I think our timing to install the new GPS station at Simeulue Airport in order to support this latest survey couldn't be better!

As we approached the northern coast of Simeulue, we started looking for potential GPS sites. Around 4 p.m. I spotted some hills that would nicely accommodate a GPS station. What made things better was that it was near Lewah, with its sheltered cove for the ship, and we still had a couple of hours to hit the shore, chat with the locals, and scout out a specific place for the GPS station.

Lewah took a direct hit from the earthquake and subsequent tsunami. Amazingly, no one, not one single person, was killed. The locals said the shaking was strong--no one could stay standing!--and lasted about two minutes with a separation of about 10 seconds between the primary and secondary earthquake waves. Once the shaking stopped, everyone ran for the highest points possible on the hills behind the village. The first wave of the tsunami train was a positive wave (where the initial tsunami wave is a crest, causing a rise in water level). Villagers across the bay said they saw a huge wave gathering offshore of Lewah, but then it broke unexpectedly several hundred meters (a few hundred yards) before hitting the village. The center of the village was hit with a surge of water about one meter (three feet) deep, but it is amazing how much of the village is intact.

The villagers indicate that sea level has dropped between one and two meters, and pointed to the exposed reef in front of the former beach as evidence. Bambang and I take all this to mean that this part of the island experienced uplift. The uplifted reef probably reduced the force of the tsunami blow considerably. There are coral micro-atolls all over the place. Some still have living tissue at their bases, while other, older ones have been exposed in their sandy graves by the December tsunamis.

We'll take time over the next few days to not only build a continuous GPS station here, but also document post-seismic uplift and tsunami parameters. We'll listen and record the stories of the villagers, hand out some relief supplies, and give a presentation tomorrow night on the science behind the earthquake and tsunamis they witnessed.

John Galetzka

For more information, see:
Sumatran Plate Boundary Project: http:/ /www.tectonics.caltech.edu/sumatra/main/public.html

An essay by Sieh that appeared in the January 10 edition of Time Asia can be viewed here.