Forecasting weathering and rock erosion through rock surface hardness: A case study on the Avşa Island granite formations

Year 2018, Issue: 1, 1 - 12, 15.10.2018

Hüseyin Turoğlu

Abstract

Rock erosion and its severity are directly proportional to the severity weathering. Erosion develops rapidly and effectively in rocks where the weathering is severe. The variations in the rock surface hardness values are indication of the weathering level of rocks. Rock surface hardness values tend to decrease on the weathered rocks. Rock surface hardness itself can be measured and classified easily using a Schmidt hammer.

The purpose of this study is to asses and analyse the rock hardness across Avşa Island (in the Marmara Sea, Turkey) using the Schmidt hammer methodology.

Rock surface hardness measurements were made on Avşa Island granites at 100 different locations using the Schmidt hammer. A statistical analysis of the measurement data was carried out followed by field controls of the new data obtained from the analysis. The results were used to create a rock surface hardness classification for Avşa Island, and were also assessed as indicators of weathering rate and erosion potential.

This new classification indicates that Avşa Island's Granite rocks can be segmented into 3 basic groups. 40% of the granites are "Hard", without serious weathering and resistant to erosion. The second group, represents 10% of the of Avşa Island's granite and is classified as "Medium to Weak". The remaining 50% Group 3 granites in the Avşa Island fall into the "Very weak" class. Group 3 granites are rocks deformed by weathering, and have high erosion potential.

Keywords

Rock surface hardness, weathering, Rock erosion, Granite weathering, Schmidt hammer

KAYA YÜZEYİ SERTLİĞİ İLE AYRIŞMA VE KAYA EROZYONUNUN TAHMİN EDİLMESİ: AVŞA ADASI GRANİT FORMASYONLARI ÜZERİNE BİR ÖRNEK ÇALIŞMA

Abstract

Kaya erozyonu ve onun şiddeti ayrışmanın şiddeti ile doğru orantılıdır. Ayrışmanın şiddetli olduğu kayalarda erozyon hızlı ve etkili olarak gelişme gösterir. Kaya yüzey sertliğindeki değişkenlik ise kayalardaki ayrışma seviyesinin göstergesidir. Ayrışmaya uğrayan kayalarda “Kaya yüzey sertliği” azalma yönünde değişim gösterir. Kaya yüzey sertliği Schmidt çekici ile ölçülebilir ve sayısal olarak ifade edilebilir, sınıflandırılabilir.   

Bu çalışmada; Avşa Adası’nda (Marmara Denizi, Türkiye), Schmidt çekici kullanılarak Granit Kaya yüzey sertliği ölçümü yapılması, sonuçların Avşa Adası için ayrışma ve erozyon göstergesi olarak değerlendirilmesi amaçlanmıştır. 

Avşa Adası granitlerinde, 100 farklı lokasyonda, Schmidt çekici kullanılarak kaya yüzey sertliği ölçümü yapılmıştır. Ölçüm verilerinin istatistiksel analizleri yapılmış, analizler ile elde edilen yeni verilerin arazi kontrolleri gerçekleştirilmiştir. İlk sonuçlar; Avşa Adası için sertlik tanımlamaları açısından sınıflandırılarak, aşınma derecesi ve erozyon potansiyeli göstergesi olarak değerlendirilmiştir.

Sonuçlar Avşa Adası'nın Granit kayalarının 3 temel grup olarak sınıflandırılabileceğini göstermektedir. Granitlerin % 40 ı “Sert” ve henüz şiddetli ayrışmaya uğramamış, erozyona karşı dirençlidir. % 10 oranındaki 2. Grup; “Orta ve Zayıf” sertliktedir. %50 oranındaki 3. Grup granitler ise “Çok Zayıf” olarak tanımlanmıştır. 3. Grup granitler şiddetli ayrışma ile deforme olan ve yüksek erozyon potansiyeline sahip kayalardır.    

Keywords

Kaya yüzey sertliği, Kaya erozyonu, Schmidt Çekici, Granit ayrışması

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